code: def _get_n_args(self, args, example, n):
          
          if len(args) != n:
              msg = (
                  'Got unexpected number of arguments, expected {}. '
                  '(example: "{} config {}")'
              ).format(n, get_prog(), example)
              raise PipError(msg)
  
          if n == 1:
              return args[0]
          else:
              return args
docs: Helper to make sure the command got the right number of arguments