def prev_sibling_position(self, pos):
        return pos[:-1] + (1 - pos[-1],) if (pos[-1] > 0) else None

    # optimizations
dataset/ETHPy150Open kdart/pycopia/QA/pycopia/QA/tui/walkers.py/SimpleTreeWalker.prev_sibling_position/swapped operands of `-`