Update app.py

app.py

@@ -564,9 +564,11 @@ if isDemo:
     currFile = file_names[0]
     isDemo = False
 
-if currFile is None and st.session_state.results:
+if currFile is None:
     st.write("Select a file to view from the sidebar")
 try:
+    if currFile is None:
+        raise ValueError("No file selected")
     st.session_state.resetResult = False
     currPlainName = currFile.split('.')[0]
     if currFile in st.session_state.results and currFile in st.session_state.summaries and len(st.session_state.results[currFile]) > 0: