modified the proxy.py. This modification shows that proxy can be used to block some operations of the other objects.

LiVincent-Zhang · LiVincent-Zhang · commit 138e5c5690b1 · 2015-04-18T13:49:03.000+08:00
diff --git a/proxy.py b/proxy.py
@@ -5,7 +5,6 @@
 
 
 class SalesManager:
-
     def work(self):
         print("Sales Manager working...")
 
@@ -14,7 +13,6 @@ def talk(self):
 
 
 class Proxy:
-
     def __init__(self):
         self.busy = 'No'
         self.sales = None
@@ -30,14 +28,32 @@ def work(self):
             print("Sales Manager is busy")
 
 
+class NoTalkProxy(Proxy):
+    def __init__(self):
+        Proxy.__init__(self)
+
+    def work(self):
+        print("Proxy checking for Sales Manager availability")
+        time.sleep(2)
+        print("This Sales Manager will not talk to you whether he/she is busy or not")
+
+
 if __name__ == '__main__':
     p = Proxy()
     p.work()
     p.busy = 'Yes'
     p.work()
+    p = NoTalkProxy()
+    p.work()
+    p.busy = 'Yse'
+    p.work()
 
 ### OUTPUT ###
 # Proxy checking for Sales Manager availability
 # Sales Manager ready to talk
 # Proxy checking for Sales Manager availability
 # Sales Manager is busy
+# Proxy checking for Sales Manager availability
+# This Sales Manager will not talk to you whether he/she is busy or not
+# Proxy checking for Sales Manager availability
+# This Sales Manager will not talk to you whether he/she is busy or not
