Collapse into a StridedInterval instance.

        :return: A new StridedInterval instance.

def collapse(self):
        """
        Collapse into a StridedInterval instance.

        :return: A new StridedInterval instance.
        """

        if self.cardinality:
            r = None
            for si in self._si_set:
                r = r._union(si) if r is not None else si

            return r

        else:
            # This is an empty StridedInterval...
            return StridedInterval.empty(self._bits)