used default dict in api_v2/event instead of normal dict

Ujesh · Ujesh · commit 984975d5d6e7 · 2021-07-22T06:35:41.000+05:30
diff --git a/4 - observer pattern/api_v2/event.py b/4 - observer pattern/api_v2/event.py
@@ -1,8 +1,9 @@
-subscribers = dict()
+from collections import defaultdict
+
+# Default value of the dictionary will be list
+subscribers = defaultdict(list)
 
 def subscribe(event_type: str, fn):
-    if not event_type in subscribers:
-        subscribers[event_type] = []
     subscribers[event_type].append(fn)
 
 def post_event(event_type: str, data):
