Method __call__

src/attr/validators.py:650–665

(self, inst, attr, value)

    )

    def __call__(self, inst, attr, value):
        try:
            self.validator(inst, attr, value)
        except self.exc_types:
            pass  # suppress error to invert validity
        else:
            raise ValueError(
                self.msg.format(
                    validator=self.validator,
                    exc_types=self.exc_types,
                ),
                attr,
                self.validator,
                value,
                self.exc_types,
            )

    def __repr__(self):
        return f"<not_ validator wrapping {self.validator!r}, capturing {self.exc_types!r}>"