diff --git a/apps/group_stat_api.py b/apps/group_stat_api.py
index 731fec9..f4eb3a4 100644
--- a/apps/group_stat_api.py
+++ b/apps/group_stat_api.py
@@ -41,6 +41,9 @@ def top_users():
 
 @group_stat_api.route("/chat_activity", methods=["GET"])
 def chat_activity():
+    dates = []
+    counts = []
+    
     from_date = request.args.get("from_date")
     to_date = request.args.get("to_date")
     
@@ -50,13 +53,10 @@ def chat_activity():
         }),422
 
     date_format = request.args.get("date_format")
-    group_by = request.args.get("group_by")
-    
-    group_by = group_by if group_by else "day"
     date_format = date_format if date_format else "%Y-%m-%d"
-     
-    dates = []
-    counts = []
+    
+    group_by = request.args.get("group_by")
+    group_by = group_by if group_by else "day"
     
     try:
         from_date = datetime.strptime(from_date, date_format)
@@ -81,9 +81,9 @@ def chat_activity():
         .order_by(SQL("range"))
     )
 
-    for group in query:
-        dates.append(group.range.strftime(date_format))
-        counts.append(group.count)
+    for row in query:
+        dates.append(row.range.strftime(date_format))
+        counts.append(row.count)
 
     return jsonify({
         "date": dates,