Return interval with bigger cardinality
        Refer Section 3.1

        :param interval1: first interval
        :param interval2: second interval
        :return: Interval or interval2 whichever has greater cardinality

def _bigger(interval1, interval2):
        """
        Return interval with bigger cardinality
        Refer Section 3.1

        :param interval1: first interval
        :param interval2: second interval
        :return: Interval or interval2 whichever has greater cardinality
        """
        if interval2.cardinality > interval1.cardinality:
            return interval2.copy()
        return interval1.copy()