def _nonmatch_class_pos(self):
        """Return the position of the non-match class."""
        # TODO: add notfitted warnings
        if self.kernel.classes_.shape[0] != 2:
            raise ValueError("Number of classes is {}, expected 2.".format(
                self.kernel.classes_.shape[0]))

        # # get the position of match probabilities
        # classes = list(self.kernel.classes_)
        # return classes.index(0)

        return 0
Return the position of the non-match class.