def _required_args(fn):
  """Returns arguments of fn with default=REQUIRED_ARG."""
  spec = getargspec(fn)
  if not spec.defaults:
    return []

  arg_names = spec.args[-len(spec.defaults):]
  return [name for name, val in zip(arg_names, spec.defaults)
          if val is REQUIRED_ARG]
def _required_args ( fn ) : spec = getargspec ( fn ) if not spec . defaults : return [ ] arg_names = spec . args [ - len ( spec . defaults ) : ] return [ name for name , val in zip ( arg_names , spec . defaults ) if val is REQUIRED_ARG ]
Returns arguments of fn with default=REQUIRED_ARG.