code: def mock_key_down(self, target, key_press_times):
          
          key = Keys.DOWN
          if key_press_times < 0:
              key = Keys.UP
  
          for i in range(abs(key_press_times)):
              rand_block(0.1, 0.01)
              target.send_keys(key)
docs: key_press_times => >= 0 则 DOWN, 否则 UP
  
          :param target:
          :type target:
          :param key_press_times:
          :type key_press_times: int
          :return:
          :rtype: