add stopper if no file

app.py

@@ -38,6 +38,8 @@ if not file_url:
     )
     file_url = st.file_uploader("Upload KML/GeoJSON file", type=["geojson", "kml", "shp"])
 
+if not file_url:
+    st.stop()
 
 if ("file_url" in st.session_state) and (st.session_state.file_url == file_url):
     # st.toast("Using cached data")