把position改成小写了，还是提示错误。如何解决？

from tqsdk import TqApi, TqAccount, TqSim

api = TqApi(TqSim())

position=api.get_position()

print(“多开均价: %.2f” % (position.open_price_long))
AttributeError: ‘Entity’ object has no attribute ‘open_price_long’