1 import contextlib #导入模块1
 2 @contextlib.contextmanager#装饰器2
 3 def myopen(f1,f2):
 4     ff = open(f1,f2,encoding='utf-8')
 5     try:
 6         yield ff#碰到yield,把ff传给with的file 4
 7     finally:
 8         ff.close()#关闭文件6
 9 
10 with myopen('f','r') as file#执行myopen函数3
11     print(file.readline())#读文件内容5