def remaining(self):
        """
        Returns the number of remaining steps of `advance()` in order to complete this constraint.
        """
        raise NotImplementedError(
            f"{self.__class__} is an abstract class. Only classes inheriting this class can be called."
        )

        Returns the number of remaining steps of `advance()` in order to complete this constraint.
        
dpkd/transformers/src/transformers/generation/beam_constraints.py