If the AnnotatedInteractions object was saved to a pickle and
        reloaded, this method remakes the BedTool objects.

def load_saved_bts(self):
        """If the AnnotatedInteractions object was saved to a pickle and
        reloaded, this method remakes the BedTool objects."""
        if self._bt1_path:
            self.bt1 = pbt.BedTool(self._bt1_path)
        if self._bt2_path:
            self.bt2 = pbt.BedTool(self._bt2_path)
        if self._bt_loop_path:
            self.bt_loop = pbt.BedTool(self._bt_loop_path)
        if self._bt_loop_inner_path:
            self.bt_loop_inner = pbt.BedTool(self._bt_loop_inner_path)