':param nested_namespace_name: When used as a subparser, options from this parser will be stored nested under
this attribute name in the root parser\'s namespace'

def __init__(self, **kwargs):

    if (u'--bugreport' in unicode_argv()):
        self._debug_tb_callback()
    self.subparsers = None
    self.raise_errors = None
    ArgParser.__init__(self, **kwargs)
    self.register(u'action', u'parsers', NestedSubparserAction)
    self.post_defaults = {}
    if kwargs.get(u'parents'):
        for parent in kwargs[u'parents']:
            if hasattr(parent, u'post_defaults'):
                self.set_post_defaults(**parent.post_defaults)
