Update app.py

app.py

@@ -61,7 +61,12 @@ def grant_access_multiple_repos(token, repo_list, username):
     Users are dereferenced by organisation.
     """
     if not token:
-        return "ERROR: Cannot grant access without a token."
+        return "ERROR: Cannot grant access without a write token."
+    if not repo_list:
+        return "ERROR: No repos selected."
+    if not username:
+        return "ERROR: No user selected."
+        
     if not isinstance(repo_list, list):
         repo_list = [repo_list]
     lusers = get_organisation(username)