diff --git a/python/fusion_engine_client/analysis/data_loader.py b/python/fusion_engine_client/analysis/data_loader.py
index 2ffdb025..9d4e7a6f 100644
--- a/python/fusion_engine_client/analysis/data_loader.py
+++ b/python/fusion_engine_client/analysis/data_loader.py
@@ -281,7 +281,7 @@ def read(self, *args, **kwargs) \
     def _read(self,
               message_types: Union[Iterable[MessageType], MessageType] = None,
               time_range: TimeRange = None,
-              source_ids: Optional[List[int]] = None,
+              source_ids: Optional[Iterable[int]] = None,
               show_progress: bool = False,
               ignore_cache: bool = False,
               max_messages: int = None, max_bytes: int = None,