Address PR comments

JDegner0129 · JDegner0129 · commit bbc174981461 · 2015-05-09T11:28:46.000-05:00
diff --git a/publish_subscribe.py b/publish_subscribe.py
@@ -17,10 +17,7 @@ def notify(self, msg):
         self.msg_queue.append(msg)
 
     def subscribe(self, msg, subscriber):
-        if msg not in self.subscribers:
-            self.subscribers[msg] = []
-
-        self.subscribers[msg].append(subscriber)
+        self.subscribers.setdefault(msg, []).append(subscriber)
 
     def unsubscribe(self, msg, subscriber):
         self.subscribers[msg].remove(subscriber)
