some new features

utils/file_handling.py

@@ -0,0 +1,15 @@
+import pandas as pd
+import os
+
+def allowed_file(filename):
+    return '.' in filename and filename.rsplit('.', 1)[1].lower() in {'csv', 'xls', 'xlsx'}
+
+def read_file(filepath):
+    if filepath.endswith('.csv'):
+        return pd.read_csv(filepath)
+    else:
+        return pd.read_excel(filepath)
+
+def save_processed_file(processed_df, filepath):
+    processed_df.to_csv(os.path.join(os.path.dirname(filepath), 'processed_' + os.path.basename(filepath)))
+    return 'processed_' + os.path.basename(filepath)