diff --git a/graphiti_core/utils/maintenance/node_operations.py b/graphiti_core/utils/maintenance/node_operations.py
index 509ed012..16622a6a 100644
--- a/graphiti_core/utils/maintenance/node_operations.py
+++ b/graphiti_core/utils/maintenance/node_operations.py
@@ -65,7 +65,7 @@ async def extract_nodes_reflexion(
     previous_episodes: list[EpisodicNode],
     node_names: list[str],
     ensure_ascii: bool = False,
-    group_id: str = '',
+    group_id: str | None = None,
 ) -> list[str]:
     # Prepare context for LLM
     context = {