docs: def select_rect(action, action_space, select_add, screen, screen2):
    """Select units within a rectangle."""
    select = spatial(action, action_space).unit_selection_rect
    out_rect = select.selection_screen_coord.add()
    screen_rect = point.Rect(screen, screen2)
    screen_rect.tl.assign_to(out_rect.p0)
    screen_rect.br.assign_to(out_rect.p1)
    select.selection_add = bool(select_add)