users_id_token.py 文件源码

def _listlike_guard(obj, name, iterable_only=False):
  """
  We frequently require passed objects to support iteration or
  containment expressions, but not be strings. (Of course, strings
  support iteration and containment, but not usefully.)  If the passed
  object is a string, we'll wrap it in a tuple and return it. If it's
  already an iterable, we'll return it as-is. Otherwise, we'll raise a
  TypeError.
  """
  required_type = (_Iterable,) if iterable_only else (_Container, _Iterable)
  required_type_name = ' or '.join(t.__name__ for t in required_type)

  if not isinstance(obj, required_type):
    raise ValueError('{} must be of type {}'.format(name, required_type_name))
  # at this point it is definitely the right type, but might be a string
  if isinstance(obj, basestring):
    logging.warning('{} passed as a string; should be list-like'.format(name))
    return (obj,)
  return obj