TargetPosTask调仓退不出循环

from tqsdk import TqApi, TargetPosTask,TqAuth
  api = TqApi(auth=TqAuth("xxx", "xxx"))
target_pos_active = TargetPosTask(api, "SHFE.rb2401", price="ACTIVE")
  target_pos_active.set_target_volume(1)  # 平所有仓位
while not target_pos_active.is_finished():
    api.wait_update()
  api.close()

成交以后一直在死循环。