Update app.py

app.py

@@ -17,7 +17,7 @@ if check_box:
     file_name = uploaded_file
 else:
     uploaded_file = st.file_uploader("Sube aquí tu archivo de excel", type=[".xls", ".xlsx", ".csv"], help=help_string)
-    file_name = uploaded_file.name
+    file_name = uploaded_file.name if uploaded_file is not None else None
 
 if uploaded_file is not None:
     # Can be used wherever a "file-like" object is accepted:
@@ -104,3 +104,4 @@ if uploaded_file is not None:
     st.write(f"Los pesos son: :green[{stocks[0]} -> {w1:,.4f}], :green[{stocks[1]} -> {w2:,.4f}], :green[{stocks[2]} -> {w3:,.4f}]")
     st.write(f"El retorno anualizado del portafolio es: :green[{yearly_returns:,.4f}]")
     st.write(f"La varianza anualizado del portafolio es: :green[{yearly_variance:,.4f}]")
+