def in_same_box(self, a, b):
        """Return ``True`` if nodes ``a`` and ``b``` are in the same box."""
        assert a in self.micro_indices
        assert b in self.micro_indices

        for part in self.partition:
            if a in part and b in part:
                return True

        return False
Return ``True`` if nodes ``a`` and ``b``` are in the same box.