def union_from_temporary_operation(self, in_place_method_name, *args, **kwargs):
        """Return union rect as if rects were changed.

        That is, as if an "in place" operation were
        performed permanently.
        """
        ### while keeping original position and size of
        ### each rect...

        with self.keep_rects_attrs("topleft", "size"):

            ### execute 'in place' method

            getattr(self, in_place_method_name)(*args, **kwargs)

            ### return union rect of rects
            return self.union_rect
Return union rect as if rects were changed.

        That is, as if an "in place" operation were
        performed permanently.
        
nodezator/rectsman/main.py