设计模式-结构型模式之外观

 1 class Valley:
 2 
 3     def run(self):
 4         self.pre_declare()
 5         self.declare()
 6         self.after_declare()
 7 
 8     def pre_declare(self):
 9         print(1)
10 
11     def declare(self):
12         print(2)
13 
14     def after_declare(self):
15         print(3)
16 
17 
18 def exec():
19     """统一内部接口"""
20     Valley().run()