class Mycontex(object):

    def __init__(self,name):

        self.name=name

    def __enter__(self):

        print("__enter__")

        return self

    def do_self(self):

        print("do_self")

    def __exit__(self,exc_type,exc_value,traceback):

        print("__exit__")

        print("Error:",exc_type,"info:",exc_value)

if __name__=="main":

    with Mycontex("test context")as f:

        print(f.name)

        f.do_self()

没运行结果