fix memory issue

dataset_script.py

@@ -250,7 +250,7 @@ class CommonVoice(datasets.GeneratorBasedBuilder):
                 if not metadata:
                     break
                 if path in metadata:
-                    result = metadata[path]
+                    result = dict(metadata[path])
                     # set the audio feature and the path to the extracted file
                     path = os.path.join(local_extracted_archive, path) if local_extracted_archive else path
                     result["audio"] = {"path": path, "bytes": f.read()}