执行结果：
"E:\Program Files\JetBrains\PycharmProjects\python_demo\venv\Scripts\python.exe" "E:/Program Files/JetBrains/PycharmProjects/python_demo/day21/module-lesson.py" 被调用文件：web.web1.web3.cal 执行文件：__main__ Process finished with exit code 0
在文件内测试在下面这句里面写，不用注释。
if __name__=="__main__":
