def __call__(self, inst, attr, value):
        """
        We use a callable class to be able to change the ``__repr__``.
        """
        if self.iterable_validator is not None:
            self.iterable_validator(inst, attr, value)

        for member in value:
            self.member_validator(inst, attr, member)

        We use a callable class to be able to change the ``__repr__``.
        
product/gradle-plugin/src/main/python/attr/validators.py