Update app.py

app.py

@@ -245,7 +245,7 @@ def certification(hf_username, first_name, last_name):
     if unit["unit"] == "Unit 6":
         # Since Unit 6 can use PandaReachDense-v2 or v3
         user_models = get_user_models(hf_username, "PandaReachDense-v3", unit["library"])
-        if user_models == "":
+        if len(user_models) == 0:
             print("Empty")
             user_models = get_user_models(hf_username, "PandaReachDense-v2", unit["library"])
     elif unit["unit"] != "Unit 8 PII":