Upload streamapp.py

streamapp.py

@@ -270,11 +270,12 @@ with tab3:
   
   
   with st.form(" trace"):
-      
-    df0 = px.active_session().get_spans_dataframe()
-    if not df0.empty:
-       df= df0.fillna('')
-       st.dataframe(df)
+
+    if px.active_session():  
+        df0 = px.active_session().get_spans_dataframe()
+        if not df0.empty:
+            df= df0.fillna('')
+            st.dataframe(df)