元素不支持下拉选择操作(win)

用设置下拉框指令提示元素不支持下拉选择操作，帮忙看下这种下拉列表自动选择怎么能用设置下拉框指定实现

 元素不支持下拉选择操作
xbot_visual.win32.element.select(window="0", element=package.selector("保质期单位下拉框"), mode="text", value="月", match_mode="exact", delay_after="0", timeout="20", _block=("子流程2", 36, "设置下拉框(win)"))
File "<string>", line 89, in wrapper
File "<string>", line 84, in wrapper
File "<string>", line 294, in select
File "<string>", line 238, in select
File "<string>", line 508, in _invoke
File "<string>", line 115, in execute
File "<string>", line 88, in execute
xbot.errors.UIAError: 元素不支持下拉选择操作