'Adds a deprecated argument with the name argument_name.
Deprecated arguments are not shown in the help. If they are used
on the command line, a warning is shown stating that the
argument is deprecated and no other action is taken.
:param str argument_name: Name of deprecated argument.
:param int nargs: Number of arguments the option takes.'

def add_deprecated_argument(self, argument_name, num_args):

    util.add_deprecated_argument(self.parser.add_argument, argument_name, num_args)
