Checks if the given limit is valid.

        A limit must be > 0 to be considered valid.

        Raises ValueError when the *limit* is not > 0.

def check_limit(self, limit):
        """
        Checks if the given limit is valid.

        A limit must be > 0 to be considered valid.

        Raises ValueError when the *limit* is not > 0.
        """
        if limit > 0:
            self.limit = limit
        else:
            raise ValueError("Rule limit must be strictly > 0 ({0} given)"
                             .format(limit))

        return self