def serialized(self):
        to_ret = {}
        for group, requirements in self.items():
            to_ret[group] = [str(requirement) for requirement in requirements]
        return to_ret
def update_state(self, y_true, y_pred, sample_weight=None):
    sample_weight = _apply_mask(y_true, sample_weight, self._masked_tokens,
                                self._dtype)
    sample_weight = tf.reshape(sample_weight, [-1])
    super().update_state(sample_weight)