Empty dict for streaming dataset

rixvox.py

@@ -120,7 +120,7 @@ class Rixvox(datasets.GeneratorBasedBuilder):
             meta_urls = {self.config.name: meta_urls[self.config.name]}
 
         archive_paths = dl_manager.download(archive_urls)
-        local_extracted_archives = dl_manager.extract(archive_paths) if not dl_manager.is_streaming else None
+        local_extracted_archives = dl_manager.extract(archive_paths) if not dl_manager.is_streaming else {}
         meta_paths = dl_manager.download(meta_urls)
 
         split_generators = []