code: def draw_selection(self, surf):
      
      select_start = self._select_start  # Cache to avoid a race condition.
      if select_start:
        mouse_pos = self.get_mouse_pos()
        if (mouse_pos and mouse_pos.surf.surf_type & SurfType.SCREEN and
            mouse_pos.surf.surf_type == select_start.surf.surf_type):
          rect = point.Rect(select_start.world_pos, mouse_pos.world_pos)
          surf.draw_rect(colors.green, rect, 1)
docs: Draw the selection rectange.