Update app.py

app.py

@@ -40,6 +40,10 @@ def classify_comments(categories):
 
 # Function to generate visualizations
 def visualize_output():
+    # Ensure the required columns exist
+    if 'comment_sentiment' not in df.columns or 'comment_category' not in df.columns:
+        return None, None, None, "Error: Please classify comments before visualizing."
+
     # Pie Chart of Sentiment
     sentiment_counts = df['comment_sentiment'].value_counts()
     sentiment_pie = px.pie(