'Adds a parser for a new subcommand and returns it.
:param name: Name of the subcommand
:param parent_defaults: Default argument values which should be supplied to the parent parser if this subparser
is selected.'

def add_subparser(self, name, **kwargs):

    if (not self.subparsers):
        raise TypeError(u'This    parser    does    not    have    subparsers')
    result = self.subparsers.add_parser(name, **kwargs)
    return result
