diff -r 2cd0aa44d53c Doc/library/argparse.rst
--- a/Doc/library/argparse.rst	Wed Jan 21 00:47:54 2015 -0500
+++ b/Doc/library/argparse.rst	Thu Jan 22 02:33:58 2015 +0000
@@ -1765,6 +1765,45 @@
    :meth:`~ArgumentParser.add_argument_group`.
 
 
+Mutual dependence
+^^^^^^^^^^^^^^^^^
+
+.. method:: ArgumentParser.add_mutually_dependence_group(required=False)
+
+   Create a mutually dependence group. :mod:`argparse` will make sure that all
+   the arguments in the mutually dependence group was present on the
+   command line::
+
+     >>> parser = argparse.ArgumentParser(prog='PROG')
+     >>> group = parser.add_mutually_dependence_group()
+     >>> group.add_argument('--foo')
+     >>> group.add_argument('--bar')
+     >>> parser.parse_args(['--foo', 'f', '--bar', 'b'])
+     Namespace(bar='b', foo='f')
+     >>> parser.parse_args(['--foo', 'f'])
+     PROG: error: --foo dependence on --bar
+     >>> parser.parse_args(['--bar', 'b'])
+     PROG: error: --bar dependence on --foo
+
+   The :meth:`add_mutually_dependence_group` method also accepts a *required*
+   argument, to indicate that all of the mutually dependence arguments is
+   required::
+
+     >>> parser = argparse.ArgumentParser(prog='PROG')
+     >>> group = parser.add_mutually_dependence_group(required=True)
+     >>> group.add_argument('--foo')
+     >>> group.add_argument('--bar')
+     >>> parser.parse_args([])
+     usage: PROG [-h] (--foo | --bar)
+     PROG: error: the arguments --foo --bar is required
+
+   Note that currently mutually dependence argument groups do not support the
+   *title* and *description* arguments of
+   :meth:`~ArgumentParser.add_argument_group`. And The ``action`` keyword argument
+   of :meth:`~ArgumentParser.add_argument` not allowed with ``'store_true'`` and
+   ``'store_false'``
+
+
 Parser defaults
 ^^^^^^^^^^^^^^^