docs: def _is_sequence(typ):
      """
      returns True if the type in question
      is a Sequence[] object from the typing module.
      """
      # PEP_560 deprecates issubclass for
      # List types, for the time being
      # we'll support a specific escape hatch.
      if PEP_560:  # pragma: no cover
          return isinstance(typ, _GenericAlias) and typ.__origin__ is list
      else:  # pragma: no cover
          return issubclass(typ, Sequence)