code: def parse_args(self, args = None, namespace = None,
                     config_file_contents = None, env_vars = os.environ):
          
          args, argv = self.parse_known_args(args = args,
              namespace = namespace,
              config_file_contents = config_file_contents,
              env_vars = env_vars)
          if argv:
              self.error('unrecognized arguments: %s' % ' '.join(argv))
          return args
docs: Supports all the same args as the ArgumentParser.parse_args(..),
          as well as the following additional args.
  
          Additional Args:
              args: a list of args as in argparse, or a string (eg. "-x -y bla")
              config_file_contents: String. Used for testing.
              env_vars: Dictionary. Used for testing.