Make a copy of self and return.

        :return: A new ValueSet object.
        :rtype: ValueSet

def copy(self):
        """
        Make a copy of self and return.

        :return: A new ValueSet object.
        :rtype: ValueSet
        """

        vs = ValueSet(bits=self.bits)
        vs._regions = self._regions.copy()
        vs._region_base_addrs = self._region_base_addrs.copy()
        vs._reversed = self._reversed
        vs._si = self._si.copy()

        return vs