Update app.py

app.py

@@ -34,6 +34,12 @@ st.markdown('##### The code expects input_data as a string or CSV file that cont
 st.markdown('##### If there are no reagents or catalysts, fill the blank with a space. And if there are multiple reactants, concatenate them with "."')
 display_text = 'input the reaction smiles (e.g. REACTANT:CC(C)n1ncnc1-c1cn2c(n1)-c1cnc(O)cc1OCC2.CCN(C(C)C)C(C)C.Cl.NC(=O)[C@@H]1C[C@H](F)CN1REAGENT: PRODUCT:O=C(NNC(=O)C(F)(F)F)C(F)(F)F)'
 
+st.download_button(
+                label="Download demo_input.csv",
+                data=pd.read_csv('demo_input.csv').to_csv(index=False),
+                file_name='demo_input.csv',
+                mime='text/csv',
+            )
 
 class CFG():
     uploaded_file = st.file_uploader("Choose a CSV file")