'This is called when :meth:`process_args` encounters an
argument it doesn\'t understand.  Override this method if you
want to be able to understand additional command line arguments.
:param args: A list of the remaining arguments.  The initial one will
have had the leading dashes removed (eg if it was --foo on the command
line then args[0] will be "foo"
:returns: None if you don\'t recognize the argument either.  Otherwise
return the list of remaining arguments after you have processed
yours.'

def process_unknown_args(self, args):

    return None
