请问如何一次性清空所有持仓，不管账户上有多少品种？

...........
orders = api.get_order()
positions = api.get_position()
target_pos_symbols = {}
a = "等待创建目标持仓任务"
b = "准备撤单"
 while True:
    api.wait_update()
    if datetime.now().hour == 14 and datetime.now().minute >= 55 and b = "准备撤单":
        [api.cancel(k) for k, v in orders.items() if v.status == "ALIVE"] 
        b = "撤单指令发出"
    if all([o.status == "FINISHED" for o in orders.values()]) and a == "等待创建目标持仓任务":
        for i in positions.keys():
            target_pos_symbols[i] = TargetPosTask(api, i)
        a = "创建目标持仓完成"
        print(a)
    if all([(v.pos_long==0 and v.pos_short==0) for v in positions.values()])
        print("订单全撤并且全平")
        break
 api.close()

这个是全撤完再全平的代码，请问在什么情况下需要去进行全平呢？