feat: Add warning for empty twitter handler input

app.py

@@ -124,4 +124,6 @@ if go_btn and tw_user != '':
     tweets_txt = list(set(tweets_txt))
     # plot = generate_plot(df, text_column, label_column, sample, dimensionality_reduction_function, model)
     plot = generate_plot(tweets_txt, model, tw_user)
-    st.bokeh_chart(plot)
+    st.bokeh_chart(plot)
+elif go_btn and tw_user == '':
+    st.warning('Twitter handler field is empty 🙄')