Update app.py

app.py

@@ -54,7 +54,7 @@ st.write('')
 st.write('')
 st.write('')
 
-
+selected_df = df.DataFrame()
 with st.form('mform', clear_on_submit=False):
     source = st.selectbox('Select the protein structure resource (1: PDB-SwissModel-Modbase, 2: AlphaFold)',[1,2])
     impute = st.selectbox('Imputation',[True, False])
@@ -106,8 +106,8 @@ with st.form('mform', clear_on_submit=False):
                 pass
         st.success('Feature vector successfully created.')
 
-        with st.form("my_form", clear_on_submit=False):
-            st.text_input("Enter filename", key="filename")
-            submit = st.form_submit_button("Download", on_click=selected_df)
+with st.form("download_form", clear_on_submit=False):
+    st.text_input("Enter filename", key="filename")
+    submit = st.form_submit_button("Download", on_click=selected_df)