First version hotfix #2

app.py

@@ -250,17 +250,17 @@ with st.sidebar:
     if uploaded_file is not None:
       date_found = False
       sales_found = False
-      for column in uploaded_file.columns:
+      df = pd.read_csv(uploaded_file, parse_dates=True)
+      for column in df.columns:
         if 'Date' in column:  
           date_found = True
         if 'Sales' in column:
           sales_found = True
-        if(date_found == False and sales_found == False):
+        if(date_found == False or sales_found == False):
           st.error('Please upload a csv containing both Date and Sales...')
           st.stop()
 
       st.success("File uploaded successfully!")
-      df = pd.read_csv(uploaded_file, parse_dates=True)
       st.write("Your uploaded data:")
       st.write(df)