@classmethod
def add_arguments(cls, parser, sys_arg_list=None):
    """
        Callback to add command line options for this plugin to the argparse
        parser.

        """
    parser.add_argument('--fixed_cidr', dest='fixed_cidr', required=True,
        help='specify the route CIDR (only in fixedconf mode)')
    parser.add_argument('--fixed_hosts', dest='fixed_hosts', required=True,
        help="list of host IPs, separated by ':' (only in fixedconf mode)")
    return ['fixed_cidr', 'fixed_hosts']
