Update app.py

app.py

@@ -77,7 +77,7 @@ def merge_models() -> None:
                                     stderr=log_file, text=True)
             print(f"mergekit: {result.stdout}")
         except subprocess.CalledProcessError as e:
-            print(f"mergekit: {e.stderr}")
+            print(f"Error: mergekit: {e.stderr}")
 
 
 def make_df(file_path: str, n_rows: int) -> pd.DataFrame: