Update app.py

app.py

@@ -218,8 +218,8 @@ class NewsGroupsDataLoader:
         test_data = dataset['test']
         
         # Combine for proper splitting
-        all_texts = train_data['text'] + test_data['text']
-        all_labels = train_data['label'] + test_data['label']
+        all_texts = list(train_data['text']) + list(test_data['text'])
+        all_labels = list(train_data['label']) + list(test_data['label'])
         
         # Get category names from dataset features
         self.categories = train_data.features['label'].names