1class CtxMgr:
2
3    def __enter__(self):
4        print("__enter__")
5        return self
6
7    def __exit__(self, a, b, c):
8        print("__exit__", repr(a), repr(b))
9
10for i in range(5):
11    print(i)
12    with CtxMgr():
13        if i == 3:
14            break
15