FM / library

/usr/share/doc/python2-docs/html/_sources/library/

/usr/share/doc/python2-docs/html/_sources/library

Name	Size	Mode	Actions
2to3.rst.txt	14647	0644	edit dl rm
abc.rst.txt	7219	0644	edit dl rm
aepack.rst.txt	4257	0644	edit dl rm
aetools.rst.txt	3532	0644	edit dl rm
aetypes.rst.txt	4257	0644	edit dl rm
aifc.rst.txt	7086	0644	edit dl rm
al.rst.txt	5309	0644	edit dl rm
allos.rst.txt	695	0644	edit dl rm
anydbm.rst.txt	4111	0644	edit dl rm
archiving.rst.txt	424	0644	edit dl rm
argparse.rst.txt	74685	0644	edit dl rm
array.rst.txt	10524	0644	edit dl rm
ast.rst.txt	10111	0644	edit dl rm
asynchat.rst.txt	9206	0644	edit dl rm
asyncore.rst.txt	12937	0644	edit dl rm
atexit.rst.txt	3910	0644	edit dl rm
audioop.rst.txt	10395	0644	edit dl rm
autogil.rst.txt	1015	0644	edit dl rm
base64.rst.txt	6252	0644	edit dl rm
basehttpserver.rst.txt	10404	0644	edit dl rm
bastion.rst.txt	2611	0644	edit dl rm
bdb.rst.txt	12456	0644	edit dl rm
binascii.rst.txt	6508	0644	edit dl rm
binhex.rst.txt	1910	0644	edit dl rm
bisect.rst.txt	5415	0644	edit dl rm
bsddb.rst.txt	7575	0644	edit dl rm
bz2.rst.txt	8064	0644	edit dl rm
calendar.rst.txt	11282	0644	edit dl rm
carbon.rst.txt	15956	0644	edit dl rm
cd.rst.txt	11974	0644	edit dl rm
cgi.rst.txt	22853	0644	edit dl rm
cgihttpserver.rst.txt	2788	0644	edit dl rm
cgitb.rst.txt	2874	0644	edit dl rm
chunk.rst.txt	4955	0644	edit dl rm
cmath.rst.txt	7647	0644	edit dl rm
cmd.rst.txt	8565	0644	edit dl rm
code.rst.txt	7115	0644	edit dl rm
codecs.rst.txt	66966	0644	edit dl rm
codeop.rst.txt	3774	0644	edit dl rm
collections.rst.txt	41448	0644	edit dl rm
colorpicker.rst.txt	913	0644	edit dl rm
colorsys.rst.txt	1819	0644	edit dl rm
commands.rst.txt	2595	0644	edit dl rm
compileall.rst.txt	4678	0644	edit dl rm
compiler.rst.txt	37464	0644	edit dl rm
configparser.rst.txt	19607	0644	edit dl rm
constants.rst.txt	2328	0644	edit dl rm
contextlib.rst.txt	6012	0644	edit dl rm
cookie.rst.txt	9543	0644	edit dl rm
cookielib.rst.txt	27875	0644	edit dl rm
copy.rst.txt	3351	0644	edit dl rm
copy_reg.rst.txt	2329	0644	edit dl rm
crypt.rst.txt	2292	0644	edit dl rm
crypto.rst.txt	355	0644	edit dl rm
csv.rst.txt	22757	0644	edit dl rm
ctypes.rst.txt	90513	0644	edit dl rm
curses.ascii.rst.txt	9046	0644	edit dl rm
curses.panel.rst.txt	2740	0644	edit dl rm
curses.rst.txt	74877	0644	edit dl rm
custominterp.rst.txt	570	0644	edit dl rm
datatypes.rst.txt	864	0644	edit dl rm
datetime.rst.txt	74679	0644	edit dl rm
dbhash.rst.txt	3865	0644	edit dl rm
dbm.rst.txt	3117	0644	edit dl rm
debug.rst.txt	446	0644	edit dl rm
decimal.rst.txt	70926	0644	edit dl rm
development.rst.txt	640	0644	edit dl rm
difflib.rst.txt	30716	0644	edit dl rm
dircache.rst.txt	1813	0644	edit dl rm
dis.rst.txt	23248	0644	edit dl rm
distribution.rst.txt	426	0644	edit dl rm
distutils.rst.txt	1958	0644	edit dl rm
dl.rst.txt	3392	0644	edit dl rm
doctest.rst.txt	73985	0644	edit dl rm
docxmlrpcserver.rst.txt	3802	0644	edit dl rm
dumbdbm.rst.txt	2841	0644	edit dl rm
dummy_thread.rst.txt	1058	0644	edit dl rm
dummy_threading.rst.txt	799	0644	edit dl rm
easydialogs.rst.txt	10346	0644	edit dl rm
email-examples.rst.txt	1271	0644	edit dl rm
email.charset.rst.txt	9654	0644	edit dl rm
email.encoders.rst.txt	2376	0644	edit dl rm
email.errors.rst.txt	4006	0644	edit dl rm
email.generator.rst.txt	6132	0644	edit dl rm
email.header.rst.txt	7531	0644	edit dl rm
email.iterators.rst.txt	2421	0644	edit dl rm
email.message.rst.txt	25217	0644	edit dl rm
email.mime.rst.txt	9917	0644	edit dl rm
email.parser.rst.txt	10327	0644	edit dl rm
email.rst.txt	16111	0644	edit dl rm
email.utils.rst.txt	6475	0644	edit dl rm
ensurepip.rst.txt	5022	0644	edit dl rm
errno.rst.txt	6708	0644	edit dl rm
exceptions.rst.txt	18343	0644	edit dl rm
fcntl.rst.txt	7361	0644	edit dl rm
filecmp.rst.txt	5348	0644	edit dl rm
fileformats.rst.txt	302	0644	edit dl rm
fileinput.rst.txt	7417	0644	edit dl rm
filesys.rst.txt	806	0644	edit dl rm
fl.rst.txt	17646	0644	edit dl rm
fm.rst.txt	2699	0644	edit dl rm
fnmatch.rst.txt	3104	0644	edit dl rm
formatter.rst.txt	13245	0644	edit dl rm
fpectl.rst.txt	4171	0644	edit dl rm
fpformat.rst.txt	1747	0644	edit dl rm
fractions.rst.txt	5297	0644	edit dl rm
framework.rst.txt	11444	0644	edit dl rm
frameworks.rst.txt	378	0644	edit dl rm
ftplib.rst.txt	15720	0644	edit dl rm
functions.rst.txt	75554	0644	edit dl rm
functools.rst.txt	7448	0644	edit dl rm
future_builtins.rst.txt	2010	0644	edit dl rm
gc.rst.txt	9014	0644	edit dl rm
gdbm.rst.txt	4882	0644	edit dl rm
gensuitemodule.rst.txt	3113	0644	edit dl rm
getopt.rst.txt	6670	0644	edit dl rm
getpass.rst.txt	1876	0644	edit dl rm
gettext.rst.txt	29040	0644	edit dl rm
gl.rst.txt	6009	0644	edit dl rm
glob.rst.txt	2414	0644	edit dl rm
grp.rst.txt	2256	0644	edit dl rm
gzip.rst.txt	4828	0644	edit dl rm
hashlib.rst.txt	7379	0644	edit dl rm
heapq.rst.txt	13185	0644	edit dl rm
hmac.rst.txt	3073	0644	edit dl rm
hotshot.rst.txt	4289	0644	edit dl rm
htmllib.rst.txt	7379	0644	edit dl rm
htmlparser.rst.txt	11640	0644	edit dl rm
httplib.rst.txt	37454	0644	edit dl rm
i18n.rst.txt	409	0644	edit dl rm
ic.rst.txt	5005	0644	edit dl rm
idle.rst.txt	22182	0644	edit dl rm
imageop.rst.txt	4001	0644	edit dl rm
imaplib.rst.txt	17221	0644	edit dl rm
imgfile.rst.txt	2765	0644	edit dl rm
imghdr.rst.txt	2635	0644	edit dl rm
imp.rst.txt	12593	0644	edit dl rm
importlib.rst.txt	1126	0644	edit dl rm
imputil.rst.txt	7023	0644	edit dl rm
index.rst.txt	2287	0644	edit dl rm
inspect.rst.txt	28151	0644	edit dl rm
internet.rst.txt	950	0644	edit dl rm
intro.rst.txt	2803	0644	edit dl rm
io.rst.txt	39015	0644	edit dl rm
ipc.rst.txt	630	0644	edit dl rm
itertools.rst.txt	36324	0644	edit dl rm
jpeg.rst.txt	3858	0644	edit dl rm
json.rst.txt	25545	0644	edit dl rm
keyword.rst.txt	617	0644	edit dl rm
language.rst.txt	523	0644	edit dl rm
linecache.rst.txt	1887	0644	edit dl rm
locale.rst.txt	24975	0644	edit dl rm
logging.config.rst.txt	31560	0644	edit dl rm
logging.handlers.rst.txt	28153	0644	edit dl rm
logging.rst.txt	46882	0644	edit dl rm
mac.rst.txt	791	0644	edit dl rm
macos.rst.txt	3824	0644	edit dl rm
macosa.rst.txt	3964	0644	edit dl rm
macostools.rst.txt	4017	0644	edit dl rm
macpath.rst.txt	650	0644	edit dl rm
mailbox.rst.txt	68129	0644	edit dl rm
mailcap.rst.txt	3675	0644	edit dl rm
markup.rst.txt	1249	0644	edit dl rm
marshal.rst.txt	5689	0644	edit dl rm
math.rst.txt	10920	0644	edit dl rm
md5.rst.txt	2815	0644	edit dl rm
mhlib.rst.txt	3966	0644	edit dl rm
mimetools.rst.txt	4504	0644	edit dl rm
mimetypes.rst.txt	9839	0644	edit dl rm
mimewriter.rst.txt	3360	0644	edit dl rm
mimify.rst.txt	3519	0644	edit dl rm
miniaeframe.rst.txt	2564	0644	edit dl rm
misc.rst.txt	248	0644	edit dl rm
mm.rst.txt	447	0644	edit dl rm
mmap.rst.txt	10481	0644	edit dl rm
modulefinder.rst.txt	3380	0644	edit dl rm
modules.rst.txt	382	0644	edit dl rm
msilib.rst.txt	19062	0644	edit dl rm
msvcrt.rst.txt	4346	0644	edit dl rm
multifile.rst.txt	6613	0644	edit dl rm
multiprocessing.rst.txt	92621	0644	edit dl rm
mutex.rst.txt	1939	0644	edit dl rm
netdata.rst.txt	432	0644	edit dl rm
netrc.rst.txt	3119	0644	edit dl rm
new.rst.txt	2653	0644	edit dl rm
nis.rst.txt	2108	0644	edit dl rm
nntplib.rst.txt	14531	0644	edit dl rm
numbers.rst.txt	8007	0644	edit dl rm
numeric.rst.txt	751	0644	edit dl rm
operator.rst.txt	22092	0644	edit dl rm
optparse.rst.txt	77101	0644	edit dl rm
os.path.rst.txt	13094	0644	edit dl rm
os.rst.txt	82580	0644	edit dl rm
ossaudiodev.rst.txt	17309	0644	edit dl rm
othergui.rst.txt	2721	0644	edit dl rm
parser.rst.txt	15385	0644	edit dl rm
pdb.rst.txt	16043	0644	edit dl rm
persistence.rst.txt	826	0644	edit dl rm
pickle.rst.txt	37262	0644	edit dl rm
pickletools.rst.txt	1997	0644	edit dl rm
pipes.rst.txt	3786	0644	edit dl rm
pkgutil.rst.txt	7714	0644	edit dl rm
platform.rst.txt	9554	0644	edit dl rm
plistlib.rst.txt	4134	0644	edit dl rm
popen2.rst.txt	7022	0644	edit dl rm
poplib.rst.txt	6220	0644	edit dl rm
posix.rst.txt	3630	0644	edit dl rm
posixfile.rst.txt	7200	0644	edit dl rm
pprint.rst.txt	9071	0644	edit dl rm
profile.rst.txt	28666	0644	edit dl rm
pty.rst.txt	1762	0644	edit dl rm
pwd.rst.txt	2725	0644	edit dl rm
pyclbr.rst.txt	3296	0644	edit dl rm
pydoc.rst.txt	4083	0644	edit dl rm
pyexpat.rst.txt	28891	0644	edit dl rm
python.rst.txt	514	0644	edit dl rm
py_compile.rst.txt	2479	0644	edit dl rm
queue.rst.txt	7034	0644	edit dl rm
quopri.rst.txt	2670	0644	edit dl rm
random.rst.txt	13319	0644	edit dl rm
re.rst.txt	55102	0644	edit dl rm
readline.rst.txt	10513	0644	edit dl rm
repr.rst.txt	4718	0644	edit dl rm
resource.rst.txt	9595	0644	edit dl rm
restricted.rst.txt	3327	0644	edit dl rm
rexec.rst.txt	11742	0644	edit dl rm
rfc822.rst.txt	14037	0644	edit dl rm
rlcompleter.rst.txt	2494	0644	edit dl rm
robotparser.rst.txt	2190	0644	edit dl rm
runpy.rst.txt	6938	0644	edit dl rm
sched.rst.txt	4644	0644	edit dl rm
scrolledtext.rst.txt	1379	0644	edit dl rm
select.rst.txt	20705	0644	edit dl rm
sets.rst.txt	14973	0644	edit dl rm
sgi.rst.txt	322	0644	edit dl rm
sgmllib.rst.txt	10664	0644	edit dl rm
sha.rst.txt	2807	0644	edit dl rm
shelve.rst.txt	8319	0644	edit dl rm
shlex.rst.txt	11313	0644	edit dl rm
shutil.rst.txt	13491	0644	edit dl rm
signal.rst.txt	10719	0644	edit dl rm
simplehttpserver.rst.txt	4559	0644	edit dl rm
simplexmlrpcserver.rst.txt	10881	0644	edit dl rm
site.rst.txt	7880	0644	edit dl rm
smtpd.rst.txt	2464	0644	edit dl rm
smtplib.rst.txt	14906	0644	edit dl rm
sndhdr.rst.txt	1759	0644	edit dl rm
socket.rst.txt	40765	0644	edit dl rm
socketserver.rst.txt	22512	0644	edit dl rm
someos.rst.txt	599	0644	edit dl rm
spwd.rst.txt	2825	0644	edit dl rm
sqlite3.rst.txt	35448	0644	edit dl rm
ssl.rst.txt	76554	0644	edit dl rm
stat.rst.txt	7778	0644	edit dl rm
statvfs.rst.txt	1300	0644	edit dl rm
stdtypes.rst.txt	122668	0644	edit dl rm
string.rst.txt	44085	0644	edit dl rm
stringio.rst.txt	4166	0644	edit dl rm
stringprep.rst.txt	4238	0644	edit dl rm
strings.rst.txt	746	0644	edit dl rm
struct.rst.txt	17100	0644	edit dl rm
subprocess.rst.txt	33648	0644	edit dl rm
sun.rst.txt	249	0644	edit dl rm
sunau.rst.txt	7124	0644	edit dl rm
sunaudio.rst.txt	5849	0644	edit dl rm
symbol.rst.txt	975	0644	edit dl rm
symtable.rst.txt	5064	0644	edit dl rm
sys.rst.txt	47520	0644	edit dl rm
sysconfig.rst.txt	7639	0644	edit dl rm
syslog.rst.txt	3931	0644	edit dl rm
tabnanny.rst.txt	1999	0644	edit dl rm
tarfile.rst.txt	28214	0644	edit dl rm
telnetlib.rst.txt	7482	0644	edit dl rm
tempfile.rst.txt	10504	0644	edit dl rm
termios.rst.txt	3733	0644	edit dl rm
test.rst.txt	17659	0644	edit dl rm
textwrap.rst.txt	8552	0644	edit dl rm
thread.rst.txt	6588	0644	edit dl rm
threading.rst.txt	32468	0644	edit dl rm
time.rst.txt	26020	0644	edit dl rm
timeit.rst.txt	11598	0644	edit dl rm
tix.rst.txt	22693	0644	edit dl rm
tk.rst.txt	1612	0644	edit dl rm
tkinter.rst.txt	33456	0644	edit dl rm
token.rst.txt	2451	0644	edit dl rm
tokenize.rst.txt	5570	0644	edit dl rm
trace.rst.txt	6724	0644	edit dl rm
traceback.rst.txt	10711	0644	edit dl rm
ttk.rst.txt	57411	0644	edit dl rm
tty.rst.txt	1011	0644	edit dl rm
turtle.rst.txt	64097	0644	edit dl rm
types.rst.txt	6200	0644	edit dl rm
undoc.rst.txt	6550	0644	edit dl rm
unicodedata.rst.txt	5736	0644	edit dl rm
unittest.rst.txt	82952	0644	edit dl rm
unix.rst.txt	490	0644	edit dl rm
urllib.rst.txt	24960	0644	edit dl rm
urllib2.rst.txt	35211	0644	edit dl rm
urlparse.rst.txt	16071	0644	edit dl rm
user.rst.txt	2748	0644	edit dl rm
userdict.rst.txt	9290	0644	edit dl rm
uu.rst.txt	2369	0644	edit dl rm
uuid.rst.txt	8378	0644	edit dl rm
warnings.rst.txt	19815	0644	edit dl rm
wave.rst.txt	5047	0644	edit dl rm
weakref.rst.txt	12926	0644	edit dl rm
webbrowser.rst.txt	9863	0644	edit dl rm
whichdb.rst.txt	931	0644	edit dl rm
windows.rst.txt	273	0644	edit dl rm
winsound.rst.txt	5066	0644	edit dl rm
wsgiref.rst.txt	30567	0644	edit dl rm
xdrlib.rst.txt	8077	0644	edit dl rm
xml.dom.minidom.rst.txt	11208	0644	edit dl rm
xml.dom.pulldom.rst.txt	1571	0644	edit dl rm
xml.dom.rst.txt	40182	0644	edit dl rm
xml.etree.elementtree.rst.txt	35707	0644	edit dl rm
xml.rst.txt	6090	0644	edit dl rm
xml.sax.handler.rst.txt	15371	0644	edit dl rm
xml.sax.reader.rst.txt	12257	0644	edit dl rm
xml.sax.rst.txt	6460	0644	edit dl rm
xml.sax.utils.rst.txt	3560	0644	edit dl rm
xmlrpclib.rst.txt	22559	0644	edit dl rm
zipfile.rst.txt	18871	0644	edit dl rm
zipimport.rst.txt	5957	0644	edit dl rm
zlib.rst.txt	12766	0644	edit dl rm
_winreg.rst.txt	23305	0644	edit dl rm
__builtin__.rst.txt	1494	0644	edit dl rm
__future__.rst.txt	4952	0644	edit dl rm
__main__.rst.txt	535	0644	edit dl rm

Edit: /usr/share/doc/python2-docs/html/_sources/library/xml.dom.rst.txt (40182B)

:mod:`xml.dom` --- The Document Object Model API
================================================

.. module:: xml.dom
   :synopsis: Document Object Model API for Python.
.. sectionauthor:: Paul Prescod <paul@prescod.net>
.. sectionauthor:: Martin v. Löwis <martin@v.loewis.de>

.. versionadded:: 2.0

The Document Object Model, or "DOM," is a cross-language API from the World Wide
Web Consortium (W3C) for accessing and modifying XML documents.  A DOM
implementation presents an XML document as a tree structure, or allows client
code to build such a structure from scratch.  It then gives access to the
structure through a set of objects which provided well-known interfaces.

The DOM is extremely useful for random-access applications.  SAX only allows you
a view of one bit of the document at a time.  If you are looking at one SAX
element, you have no access to another.  If you are looking at a text node, you
have no access to a containing element. When you write a SAX application, you
need to keep track of your program's position in the document somewhere in your
own code.  SAX does not do it for you.  Also, if you need to look ahead in the
XML document, you are just out of luck.

Some applications are simply impossible in an event driven model with no access
to a tree.  Of course you could build some sort of tree yourself in SAX events,
but the DOM allows you to avoid writing that code.  The DOM is a standard tree
representation for XML data.

The Document Object Model is being defined by the W3C in stages, or "levels" in
their terminology.  The Python mapping of the API is substantially based on the
DOM Level 2 recommendation.

.. XXX PyXML is dead...
.. The mapping of the Level 3 specification, currently
   only available in draft form, is being developed by the `Python XML Special
   Interest Group <https://www.python.org/sigs/xml-sig/>`_ as part of the `PyXML
   package <http://pyxml.sourceforge.net/>`_.  Refer to the documentation bundled
   with that package for information on the current state of DOM Level 3 support.

.. What if your needs are somewhere between SAX and the DOM?  Perhaps
   you cannot afford to load the entire tree in memory but you find the
   SAX model somewhat cumbersome and low-level.  There is also a module
   called xml.dom.pulldom that allows you to build trees of only the
   parts of a document that you need structured access to.  It also has
   features that allow you to find your way around the DOM.
   See http://www.prescod.net/python/pulldom

DOM applications typically start by parsing some XML into a DOM.  How this is
accomplished is not covered at all by DOM Level 1, and Level 2 provides only
limited improvements: There is a :class:`DOMImplementation` object class which
provides access to :class:`Document` creation methods, but no way to access an
XML reader/parser/Document builder in an implementation-independent way. There
is also no well-defined way to access these methods without an existing
:class:`Document` object.  In Python, each DOM implementation will provide a
function :func:`getDOMImplementation`. DOM Level 3 adds a Load/Store
specification, which defines an interface to the reader, but this is not yet
available in the Python standard library.

Once you have a DOM document object, you can access the parts of your XML
document through its properties and methods.  These properties are defined in
the DOM specification; this portion of the reference manual describes the
interpretation of the specification in Python.

The specification provided by the W3C defines the DOM API for Java, ECMAScript,
and OMG IDL.  The Python mapping defined here is based in large part on the IDL
version of the specification, but strict compliance is not required (though
implementations are free to support the strict mapping from IDL).  See section
:ref:`dom-conformance` for a detailed discussion of mapping requirements.

.. seealso::

`Document Object Model (DOM) Level 2 Specification <https://www.w3.org/TR/DOM-Level-2-Core/>`_
      The W3C recommendation upon which the Python DOM API is based.

`Document Object Model (DOM) Level 1 Specification <https://www.w3.org/TR/REC-DOM-Level-1/>`_
      The W3C recommendation for the DOM supported by :mod:`xml.dom.minidom`.

`Python Language Mapping Specification <http://www.omg.org/spec/PYTH/1.2/PDF>`_
      This specifies the mapping from OMG IDL to Python.

Module Contents
---------------

The :mod:`xml.dom` contains the following functions:

.. function:: registerDOMImplementation(name, factory)

Register the *factory* function with the name *name*.  The factory function
   should return an object which implements the :class:`DOMImplementation`
   interface.  The factory function can return the same object every time, or a new
   one for each call, as appropriate for the specific implementation (e.g. if that
   implementation supports some customization).

.. function:: getDOMImplementation([name[, features]])

Return a suitable DOM implementation. The *name* is either well-known, the
   module name of a DOM implementation, or ``None``. If it is not ``None``, imports
   the corresponding module and returns a :class:`DOMImplementation` object if the
   import succeeds.  If no name is given, and if the environment variable
   :envvar:`PYTHON_DOM` is set, this variable is used to find the implementation.

If name is not given, this examines the available implementations to find one
   with the required feature set.  If no implementation can be found, raise an
   :exc:`ImportError`.  The features list must be a sequence of ``(feature,
   version)`` pairs which are passed to the :meth:`hasFeature` method on available
   :class:`DOMImplementation` objects.

Some convenience constants are also provided:

.. data:: EMPTY_NAMESPACE

The value used to indicate that no namespace is associated with a node in the
   DOM.  This is typically found as the :attr:`namespaceURI` of a node, or used as
   the *namespaceURI* parameter to a namespaces-specific method.

.. versionadded:: 2.2

.. data:: XML_NAMESPACE

The namespace URI associated with the reserved prefix ``xml``, as defined by
   `Namespaces in XML <https://www.w3.org/TR/REC-xml-names/>`_ (section 4).

.. versionadded:: 2.2

.. data:: XMLNS_NAMESPACE

The namespace URI for namespace declarations, as defined by `Document Object
   Model (DOM) Level 2 Core Specification
   <https://www.w3.org/TR/DOM-Level-2-Core/core.html>`_ (section 1.1.8).

.. versionadded:: 2.2

.. data:: XHTML_NAMESPACE

The URI of the XHTML namespace as defined by `XHTML 1.0: The Extensible
   HyperText Markup Language <https://www.w3.org/TR/xhtml1/>`_ (section 3.1.1).

.. versionadded:: 2.2

In addition, :mod:`xml.dom` contains a base :class:`Node` class and the DOM
exception classes.  The :class:`Node` class provided by this module does not
implement any of the methods or attributes defined by the DOM specification;
concrete DOM implementations must provide those.  The :class:`Node` class
provided as part of this module does provide the constants used for the
:attr:`nodeType` attribute on concrete :class:`Node` objects; they are located
within the class rather than at the module level to conform with the DOM
specifications.

.. Should the Node documentation go here?

.. _dom-objects:

Objects in the DOM
------------------

The definitive documentation for the DOM is the DOM specification from the W3C.

Note that DOM attributes may also be manipulated as nodes instead of as simple
strings.  It is fairly rare that you must do this, however, so this usage is not
yet documented.

An additional section describes the exceptions defined for working with the DOM
in Python.

.. _dom-implementation-objects:

DOMImplementation Objects
^^^^^^^^^^^^^^^^^^^^^^^^^

The :class:`DOMImplementation` interface provides a way for applications to
determine the availability of particular features in the DOM they are using.
DOM Level 2 added the ability to create new :class:`Document` and
:class:`DocumentType` objects using the :class:`DOMImplementation` as well.

.. method:: DOMImplementation.hasFeature(feature, version)

Return true if the feature identified by the pair of strings *feature* and
   *version* is implemented.

.. method:: DOMImplementation.createDocument(namespaceUri, qualifiedName, doctype)

Return a new :class:`Document` object (the root of the DOM), with a child
   :class:`Element` object having the given *namespaceUri* and *qualifiedName*. The
   *doctype* must be a :class:`DocumentType` object created by
   :meth:`createDocumentType`, or ``None``. In the Python DOM API, the first two
   arguments can also be ``None`` in order to indicate that no :class:`Element`
   child is to be created.

.. method:: DOMImplementation.createDocumentType(qualifiedName, publicId, systemId)

Return a new :class:`DocumentType` object that encapsulates the given
   *qualifiedName*, *publicId*, and *systemId* strings, representing the
   information contained in an XML document type declaration.

.. _dom-node-objects:

Node Objects
^^^^^^^^^^^^

All of the components of an XML document are subclasses of :class:`Node`.

.. attribute:: Node.nodeType

An integer representing the node type.  Symbolic constants for the types are on
   the :class:`Node` object: :const:`ELEMENT_NODE`, :const:`ATTRIBUTE_NODE`,
   :const:`TEXT_NODE`, :const:`CDATA_SECTION_NODE`, :const:`ENTITY_NODE`,
   :const:`PROCESSING_INSTRUCTION_NODE`, :const:`COMMENT_NODE`,
   :const:`DOCUMENT_NODE`, :const:`DOCUMENT_TYPE_NODE`, :const:`NOTATION_NODE`.
   This is a read-only attribute.

.. attribute:: Node.parentNode

The parent of the current node, or ``None`` for the document node. The value is
   always a :class:`Node` object or ``None``.  For :class:`Element` nodes, this
   will be the parent element, except for the root element, in which case it will
   be the :class:`Document` object. For :class:`Attr` nodes, this is always
   ``None``. This is a read-only attribute.

.. attribute:: Node.attributes

A :class:`NamedNodeMap` of attribute objects.  Only elements have actual values
   for this; others provide ``None`` for this attribute. This is a read-only
   attribute.

.. attribute:: Node.previousSibling

The node that immediately precedes this one with the same parent.  For
   instance the element with an end-tag that comes just before the *self*
   element's start-tag.  Of course, XML documents are made up of more than just
   elements so the previous sibling could be text, a comment, or something else.
   If this node is the first child of the parent, this attribute will be
   ``None``. This is a read-only attribute.

.. attribute:: Node.nextSibling

The node that immediately follows this one with the same parent.  See also
   :attr:`previousSibling`.  If this is the last child of the parent, this
   attribute will be ``None``. This is a read-only attribute.

.. attribute:: Node.childNodes

A list of nodes contained within this node. This is a read-only attribute.

.. attribute:: Node.firstChild

The first child of the node, if there are any, or ``None``. This is a read-only
   attribute.

.. attribute:: Node.lastChild

The last child of the node, if there are any, or ``None``. This is a read-only
   attribute.

.. attribute:: Node.localName

The part of the :attr:`tagName` following the colon if there is one, else the
   entire :attr:`tagName`.  The value is a string.

.. attribute:: Node.prefix

The part of the :attr:`tagName` preceding the colon if there is one, else the
   empty string.  The value is a string, or ``None``.

.. attribute:: Node.namespaceURI

The namespace associated with the element name.  This will be a string or
   ``None``.  This is a read-only attribute.

.. attribute:: Node.nodeName

This has a different meaning for each node type; see the DOM specification for
   details.  You can always get the information you would get here from another
   property such as the :attr:`tagName` property for elements or the :attr:`name`
   property for attributes. For all node types, the value of this attribute will be
   either a string or ``None``.  This is a read-only attribute.

.. attribute:: Node.nodeValue

This has a different meaning for each node type; see the DOM specification for
   details.  The situation is similar to that with :attr:`nodeName`.  The value is
   a string or ``None``.

.. method:: Node.hasAttributes()

Returns true if the node has any attributes.

.. method:: Node.hasChildNodes()

Returns true if the node has any child nodes.

.. method:: Node.isSameNode(other)

Returns true if *other* refers to the same node as this node. This is especially
   useful for DOM implementations which use any sort of proxy architecture (because
   more than one object can refer to the same node).

.. note::

This is based on a proposed DOM Level 3 API which is still in the "working
      draft" stage, but this particular interface appears uncontroversial.  Changes
      from the W3C will not necessarily affect this method in the Python DOM interface
      (though any new W3C API for this would also be supported).

.. method:: Node.appendChild(newChild)

Add a new child node to this node at the end of the list of
   children, returning *newChild*. If the node was already in
   the tree, it is removed first.

.. method:: Node.insertBefore(newChild, refChild)

Insert a new child node before an existing child.  It must be the case that
   *refChild* is a child of this node; if not, :exc:`ValueError` is raised.
   *newChild* is returned. If *refChild* is ``None``, it inserts *newChild* at the
   end of the children's list.

.. method:: Node.removeChild(oldChild)

Remove a child node.  *oldChild* must be a child of this node; if not,
   :exc:`ValueError` is raised.  *oldChild* is returned on success.  If *oldChild*
   will not be used further, its :meth:`unlink` method should be called.

.. method:: Node.replaceChild(newChild, oldChild)

Replace an existing node with a new node. It must be the case that  *oldChild*
   is a child of this node; if not, :exc:`ValueError` is raised.

.. method:: Node.normalize()

Join adjacent text nodes so that all stretches of text are stored as single
   :class:`Text` instances.  This simplifies processing text from a DOM tree for
   many applications.

.. versionadded:: 2.1

.. method:: Node.cloneNode(deep)

Clone this node.  Setting *deep* means to clone all child nodes as well.  This
   returns the clone.

.. _dom-nodelist-objects:

NodeList Objects
^^^^^^^^^^^^^^^^

A :class:`NodeList` represents a sequence of nodes.  These objects are used in
two ways in the DOM Core recommendation:  an :class:`Element` object provides
one as its list of child nodes, and the :meth:`getElementsByTagName` and
:meth:`getElementsByTagNameNS` methods of :class:`Node` return objects with this
interface to represent query results.

The DOM Level 2 recommendation defines one method and one attribute for these
objects:

.. method:: NodeList.item(i)

Return the *i*'th item from the sequence, if there is one, or ``None``.  The
   index *i* is not allowed to be less than zero or greater than or equal to the
   length of the sequence.

.. attribute:: NodeList.length

The number of nodes in the sequence.

In addition, the Python DOM interface requires that some additional support is
provided to allow :class:`NodeList` objects to be used as Python sequences.  All
:class:`NodeList` implementations must include support for
:meth:`~object.__len__` and
:meth:`~object.__getitem__`; this allows iteration over the :class:`NodeList` in
:keyword:`for` statements and proper support for the :func:`len` built-in
function.

If a DOM implementation supports modification of the document, the
:class:`NodeList` implementation must also support the
:meth:`~object.__setitem__` and :meth:`~object.__delitem__` methods.

.. _dom-documenttype-objects:

DocumentType Objects
^^^^^^^^^^^^^^^^^^^^

Information about the notations and entities declared by a document (including
the external subset if the parser uses it and can provide the information) is
available from a :class:`DocumentType` object.  The :class:`DocumentType` for a
document is available from the :class:`Document` object's :attr:`doctype`
attribute; if there is no ``DOCTYPE`` declaration for the document, the
document's :attr:`doctype` attribute will be set to ``None`` instead of an
instance of this interface.

:class:`DocumentType` is a specialization of :class:`Node`, and adds the
following attributes:

.. attribute:: DocumentType.publicId

The public identifier for the external subset of the document type definition.
   This will be a string or ``None``.

.. attribute:: DocumentType.systemId

The system identifier for the external subset of the document type definition.
   This will be a URI as a string, or ``None``.

.. attribute:: DocumentType.internalSubset

A string giving the complete internal subset from the document. This does not
   include the brackets which enclose the subset.  If the document has no internal
   subset, this should be ``None``.

.. attribute:: DocumentType.name

The name of the root element as given in the ``DOCTYPE`` declaration, if
   present.

.. attribute:: DocumentType.entities

This is a :class:`NamedNodeMap` giving the definitions of external entities.
   For entity names defined more than once, only the first definition is provided
   (others are ignored as required by the XML recommendation).  This may be
   ``None`` if the information is not provided by the parser, or if no entities are
   defined.

.. attribute:: DocumentType.notations

This is a :class:`NamedNodeMap` giving the definitions of notations. For
   notation names defined more than once, only the first definition is provided
   (others are ignored as required by the XML recommendation).  This may be
   ``None`` if the information is not provided by the parser, or if no notations
   are defined.

.. _dom-document-objects:

Document Objects
^^^^^^^^^^^^^^^^

A :class:`Document` represents an entire XML document, including its constituent
elements, attributes, processing instructions, comments etc.  Remember that it
inherits properties from :class:`Node`.

.. attribute:: Document.documentElement

The one and only root element of the document.

.. method:: Document.createElement(tagName)

Create and return a new element node.  The element is not inserted into the
   document when it is created.  You need to explicitly insert it with one of the
   other methods such as :meth:`insertBefore` or :meth:`appendChild`.

.. method:: Document.createElementNS(namespaceURI, tagName)

Create and return a new element with a namespace.  The *tagName* may have a
   prefix.  The element is not inserted into the document when it is created.  You
   need to explicitly insert it with one of the other methods such as
   :meth:`insertBefore` or :meth:`appendChild`.

.. method:: Document.createTextNode(data)

Create and return a text node containing the data passed as a parameter.  As
   with the other creation methods, this one does not insert the node into the
   tree.

.. method:: Document.createComment(data)

Create and return a comment node containing the data passed as a parameter.  As
   with the other creation methods, this one does not insert the node into the
   tree.

.. method:: Document.createProcessingInstruction(target, data)

Create and return a processing instruction node containing the *target* and
   *data* passed as parameters.  As with the other creation methods, this one does
   not insert the node into the tree.

.. method:: Document.createAttribute(name)

Create and return an attribute node.  This method does not associate the
   attribute node with any particular element.  You must use
   :meth:`setAttributeNode` on the appropriate :class:`Element` object to use the
   newly created attribute instance.

.. method:: Document.createAttributeNS(namespaceURI, qualifiedName)

Create and return an attribute node with a namespace.  The *tagName* may have a
   prefix.  This method does not associate the attribute node with any particular
   element.  You must use :meth:`setAttributeNode` on the appropriate
   :class:`Element` object to use the newly created attribute instance.

.. method:: Document.getElementsByTagName(tagName)

Search for all descendants (direct children, children's children, etc.) with a
   particular element type name.

.. method:: Document.getElementsByTagNameNS(namespaceURI, localName)

Search for all descendants (direct children, children's children, etc.) with a
   particular namespace URI and localname.  The localname is the part of the
   namespace after the prefix.

.. _dom-element-objects:

Element Objects
^^^^^^^^^^^^^^^

:class:`Element` is a subclass of :class:`Node`, so inherits all the attributes
of that class.

.. attribute:: Element.tagName

The element type name.  In a namespace-using document it may have colons in it.
   The value is a string.

.. method:: Element.getElementsByTagName(tagName)

Same as equivalent method in the :class:`Document` class.

.. method:: Element.getElementsByTagNameNS(namespaceURI, localName)

Same as equivalent method in the :class:`Document` class.

.. method:: Element.hasAttribute(name)

Returns true if the element has an attribute named by *name*.

.. method:: Element.hasAttributeNS(namespaceURI, localName)

Returns true if the element has an attribute named by *namespaceURI* and
   *localName*.

.. method:: Element.getAttribute(name)

Return the value of the attribute named by *name* as a string. If no such
   attribute exists, an empty string is returned, as if the attribute had no value.

.. method:: Element.getAttributeNode(attrname)

Return the :class:`Attr` node for the attribute named by *attrname*.

.. method:: Element.getAttributeNS(namespaceURI, localName)

Return the value of the attribute named by *namespaceURI* and *localName* as a
   string. If no such attribute exists, an empty string is returned, as if the
   attribute had no value.

.. method:: Element.getAttributeNodeNS(namespaceURI, localName)

Return an attribute value as a node, given a *namespaceURI* and *localName*.

.. method:: Element.removeAttribute(name)

Remove an attribute by name.  If there is no matching attribute, a
   :exc:`NotFoundErr` is raised.

.. method:: Element.removeAttributeNode(oldAttr)

Remove and return *oldAttr* from the attribute list, if present. If *oldAttr* is
   not present, :exc:`NotFoundErr` is raised.

.. method:: Element.removeAttributeNS(namespaceURI, localName)

Remove an attribute by name.  Note that it uses a localName, not a qname.  No
   exception is raised if there is no matching attribute.

.. method:: Element.setAttribute(name, value)

Set an attribute value from a string.

.. method:: Element.setAttributeNode(newAttr)

Add a new attribute node to the element, replacing an existing attribute if
   necessary if the :attr:`name` attribute matches.  If a replacement occurs, the
   old attribute node will be returned.  If *newAttr* is already in use,
   :exc:`InuseAttributeErr` will be raised.

.. method:: Element.setAttributeNodeNS(newAttr)

Add a new attribute node to the element, replacing an existing attribute if
   necessary if the :attr:`namespaceURI` and :attr:`localName` attributes match.
   If a replacement occurs, the old attribute node will be returned.  If *newAttr*
   is already in use, :exc:`InuseAttributeErr` will be raised.

.. method:: Element.setAttributeNS(namespaceURI, qname, value)

Set an attribute value from a string, given a *namespaceURI* and a *qname*.
   Note that a qname is the whole attribute name.  This is different than above.

.. _dom-attr-objects:

Attr Objects
^^^^^^^^^^^^

:class:`Attr` inherits from :class:`Node`, so inherits all its attributes.

.. attribute:: Attr.name

The attribute name.
   In a namespace-using document it may include a colon.

.. attribute:: Attr.localName

The part of the name following the colon if there is one, else the
   entire name.
   This is a read-only attribute.

.. attribute:: Attr.prefix

The part of the name preceding the colon if there is one, else the
   empty string.

.. attribute:: Attr.value

The text value of the attribute.  This is a synonym for the
   :attr:`nodeValue` attribute.

.. _dom-attributelist-objects:

NamedNodeMap Objects
^^^^^^^^^^^^^^^^^^^^

:class:`NamedNodeMap` does *not* inherit from :class:`Node`.

.. attribute:: NamedNodeMap.length

The length of the attribute list.

.. method:: NamedNodeMap.item(index)

Return an attribute with a particular index.  The order you get the attributes
   in is arbitrary but will be consistent for the life of a DOM.  Each item is an
   attribute node.  Get its value with the :attr:`value` attribute.

There are also experimental methods that give this class more mapping behavior.
You can use them or you can use the standardized :meth:`getAttribute\*` family
of methods on the :class:`Element` objects.

.. _dom-comment-objects:

Comment Objects
^^^^^^^^^^^^^^^

:class:`Comment` represents a comment in the XML document.  It is a subclass of
:class:`Node`, but cannot have child nodes.

.. attribute:: Comment.data

The content of the comment as a string.  The attribute contains all characters
   between the leading ``<!-``\ ``-`` and trailing ``-``\ ``->``, but does not
   include them.

.. _dom-text-objects:

Text and CDATASection Objects
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The :class:`Text` interface represents text in the XML document.  If the parser
and DOM implementation support the DOM's XML extension, portions of the text
enclosed in CDATA marked sections are stored in :class:`CDATASection` objects.
These two interfaces are identical, but provide different values for the
:attr:`nodeType` attribute.

These interfaces extend the :class:`Node` interface.  They cannot have child
nodes.

.. attribute:: Text.data

The content of the text node as a string.

.. note::

The use of a :class:`CDATASection` node does not indicate that the node
   represents a complete CDATA marked section, only that the content of the node
   was part of a CDATA section.  A single CDATA section may be represented by more
   than one node in the document tree.  There is no way to determine whether two
   adjacent :class:`CDATASection` nodes represent different CDATA marked sections.

.. _dom-pi-objects:

ProcessingInstruction Objects
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Represents a processing instruction in the XML document; this inherits from the
:class:`Node` interface and cannot have child nodes.

.. attribute:: ProcessingInstruction.target

The content of the processing instruction up to the first whitespace character.
   This is a read-only attribute.

.. attribute:: ProcessingInstruction.data

The content of the processing instruction following the first whitespace
   character.

.. _dom-exceptions:

Exceptions
^^^^^^^^^^

.. versionadded:: 2.1

The DOM Level 2 recommendation defines a single exception, :exc:`DOMException`,
and a number of constants that allow applications to determine what sort of
error occurred. :exc:`DOMException` instances carry a :attr:`code` attribute
that provides the appropriate value for the specific exception.

The Python DOM interface provides the constants, but also expands the set of
exceptions so that a specific exception exists for each of the exception codes
defined by the DOM.  The implementations must raise the appropriate specific
exception, each of which carries the appropriate value for the :attr:`code`
attribute.

.. exception:: DOMException

Base exception class used for all specific DOM exceptions.  This exception class
   cannot be directly instantiated.

.. exception:: DomstringSizeErr

Raised when a specified range of text does not fit into a string. This is not
   known to be used in the Python DOM implementations, but may be received from DOM
   implementations not written in Python.

.. exception:: HierarchyRequestErr

Raised when an attempt is made to insert a node where the node type is not
   allowed.

.. exception:: IndexSizeErr

Raised when an index or size parameter to a method is negative or exceeds the
   allowed values.

.. exception:: InuseAttributeErr

Raised when an attempt is made to insert an :class:`Attr` node that is already
   present elsewhere in the document.

.. exception:: InvalidAccessErr

Raised if a parameter or an operation is not supported on the underlying object.

.. exception:: InvalidCharacterErr

This exception is raised when a string parameter contains a character that is
   not permitted in the context it's being used in by the XML 1.0 recommendation.
   For example, attempting to create an :class:`Element` node with a space in the
   element type name will cause this error to be raised.

.. exception:: InvalidModificationErr

Raised when an attempt is made to modify the type of a node.

.. exception:: InvalidStateErr

Raised when an attempt is made to use an object that is not defined or is no
   longer usable.

.. exception:: NamespaceErr

If an attempt is made to change any object in a way that is not permitted with
   regard to the `Namespaces in XML <https://www.w3.org/TR/REC-xml-names/>`_
   recommendation, this exception is raised.

.. exception:: NotFoundErr

Exception when a node does not exist in the referenced context.  For example,
   :meth:`NamedNodeMap.removeNamedItem` will raise this if the node passed in does
   not exist in the map.

.. exception:: NotSupportedErr

Raised when the implementation does not support the requested type of object or
   operation.

.. exception:: NoDataAllowedErr

This is raised if data is specified for a node which does not support data.

.. XXX  a better explanation is needed!

.. exception:: NoModificationAllowedErr

Raised on attempts to modify an object where modifications are not allowed (such
   as for read-only nodes).

.. exception:: SyntaxErr

Raised when an invalid or illegal string is specified.

.. XXX  how is this different from InvalidCharacterErr?

.. exception:: WrongDocumentErr

Raised when a node is inserted in a different document than it currently belongs
   to, and the implementation does not support migrating the node from one document
   to the other.

The exception codes defined in the DOM recommendation map to the exceptions
described above according to this table:

+--------------------------------------+---------------------------------+
| Constant                             | Exception                       |
+======================================+=================================+
| :const:`DOMSTRING_SIZE_ERR`          | :exc:`DomstringSizeErr`         |
+--------------------------------------+---------------------------------+
| :const:`HIERARCHY_REQUEST_ERR`       | :exc:`HierarchyRequestErr`      |
+--------------------------------------+---------------------------------+
| :const:`INDEX_SIZE_ERR`              | :exc:`IndexSizeErr`             |
+--------------------------------------+---------------------------------+
| :const:`INUSE_ATTRIBUTE_ERR`         | :exc:`InuseAttributeErr`        |
+--------------------------------------+---------------------------------+
| :const:`INVALID_ACCESS_ERR`          | :exc:`InvalidAccessErr`         |
+--------------------------------------+---------------------------------+
| :const:`INVALID_CHARACTER_ERR`       | :exc:`InvalidCharacterErr`      |
+--------------------------------------+---------------------------------+
| :const:`INVALID_MODIFICATION_ERR`    | :exc:`InvalidModificationErr`   |
+--------------------------------------+---------------------------------+
| :const:`INVALID_STATE_ERR`           | :exc:`InvalidStateErr`          |
+--------------------------------------+---------------------------------+
| :const:`NAMESPACE_ERR`               | :exc:`NamespaceErr`             |
+--------------------------------------+---------------------------------+
| :const:`NOT_FOUND_ERR`               | :exc:`NotFoundErr`              |
+--------------------------------------+---------------------------------+
| :const:`NOT_SUPPORTED_ERR`           | :exc:`NotSupportedErr`          |
+--------------------------------------+---------------------------------+
| :const:`NO_DATA_ALLOWED_ERR`         | :exc:`NoDataAllowedErr`         |
+--------------------------------------+---------------------------------+
| :const:`NO_MODIFICATION_ALLOWED_ERR` | :exc:`NoModificationAllowedErr` |
+--------------------------------------+---------------------------------+
| :const:`SYNTAX_ERR`                  | :exc:`SyntaxErr`                |
+--------------------------------------+---------------------------------+
| :const:`WRONG_DOCUMENT_ERR`          | :exc:`WrongDocumentErr`         |
+--------------------------------------+---------------------------------+

.. _dom-conformance:

Conformance
-----------

This section describes the conformance requirements and relationships between
the Python DOM API, the W3C DOM recommendations, and the OMG IDL mapping for
Python.

.. _dom-type-mapping:

Type Mapping
^^^^^^^^^^^^

The primitive IDL types used in the DOM specification are mapped to Python types
according to the following table.

+------------------+-------------------------------------------+
| IDL Type         | Python Type                               |
+==================+===========================================+
| ``boolean``      | ``IntegerType`` (with a value of ``0`` or |
|                  | ``1``)                                    |
+------------------+-------------------------------------------+
| ``int``          | ``IntegerType``                           |
+------------------+-------------------------------------------+
| ``long int``     | ``IntegerType``                           |
+------------------+-------------------------------------------+
| ``unsigned int`` | ``IntegerType``                           |
+------------------+-------------------------------------------+

Additionally, the :class:`DOMString` defined in the recommendation is mapped to
a Python string or Unicode string.  Applications should be able to handle
Unicode whenever a string is returned from the DOM.

The IDL ``null`` value is mapped to ``None``, which may be accepted or
provided by the implementation whenever ``null`` is allowed by the API.

.. _dom-accessor-methods:

Accessor Methods
^^^^^^^^^^^^^^^^

The mapping from OMG IDL to Python defines accessor functions for IDL
``attribute`` declarations in much the way the Java mapping does.
Mapping the IDL declarations ::

readonly attribute string someValue;
            attribute string anotherValue;

yields three accessor functions:  a "get" method for :attr:`someValue`
(:meth:`_get_someValue`), and "get" and "set" methods for :attr:`anotherValue`
(:meth:`_get_anotherValue` and :meth:`_set_anotherValue`).  The mapping, in
particular, does not require that the IDL attributes are accessible as normal
Python attributes:  ``object.someValue`` is *not* required to work, and may
raise an :exc:`AttributeError`.

The Python DOM API, however, *does* require that normal attribute access work.
This means that the typical surrogates generated by Python IDL compilers are not
likely to work, and wrapper objects may be needed on the client if the DOM
objects are accessed via CORBA. While this does require some additional
consideration for CORBA DOM clients, the implementers with experience using DOM
over CORBA from Python do not consider this a problem.  Attributes that are
declared ``readonly`` may not restrict write access in all DOM
implementations.

In the Python DOM API, accessor functions are not required.  If provided, they
should take the form defined by the Python IDL mapping, but these methods are
considered unnecessary since the attributes are accessible directly from Python.
"Set" accessors should never be provided for ``readonly`` attributes.

The IDL definitions do not fully embody the requirements of the W3C DOM API,
such as the notion of certain objects, such as the return value of
:meth:`getElementsByTagName`, being "live".  The Python DOM API does not require
implementations to enforce such requirements.

cmd: