A function decorator for defining a multi-flag validator.

    flag_names, message='Flag validation failed', flag_values=_flagvalues.FLAGS

Registers the decorated function as a validator for flag_names, e.g.

@flags.multi_flags_validator(['foo', 'bar']) def _CheckFooBar(flags_dict): ...

See register_multi_flags_validator() for the specification of checker function.


  • flag_names: [str], a list of the flag names to be checked.
  • message: str, error text to be shown to the user if checker returns False. If checker raises flags.ValidationError, message from the raised error will be shown.
  • flag_values: flags.FlagValues, optional FlagValues instance to validate against.


A function decorator that registers its function argument as a validator.


  • AttributeError: Raised when a flag is not registered as a valid flag name.