only count events with product

recommendation_engine.py

@@ -65,6 +65,7 @@ class Engine:
         # Count tags for the user
         count = defaultdict(lambda: 0)
         for event in user.get('events', []):
+            if event.get('data', {}).get('product'):
                 count[event['data']['product']] += 1
         # For each tag in playlist, increment score by count
         for playlist in playlists: