diff --git a/mitm_tooling/representation/sql_representation.py b/mitm_tooling/representation/sql_representation.py
index 4a88a8a143ec1884e28051c694e418c639d6acae..d9a1656ca3253bfa853b86c0667c11d53e076ea2 100644
--- a/mitm_tooling/representation/sql_representation.py
+++ b/mitm_tooling/representation/sql_representation.py
@@ -418,7 +418,7 @@ def insert_mitm_data_instances(bind: AnyDBBind, sql_rep_schema: SQLRepresentatio
     int, int]:
     from mitm_tooling.transformation.df import mitm_data_into_mitm_dataframes
     mitm_dataframes = mitm_data_into_mitm_dataframes(mitm_data)
-    instances = ((t, (df,) for t, df in dfs.items()) for c, dfs in mitm_dataframes)
+    instances: Iterable[tuple[ConceptName, Iterable[tuple[TypeName, Iterable[pd.DataFrame]]]]] = ((c, ((t, (df,)) for t, df in dfs.items())) for c, dfs in mitm_dataframes)
     return insert_instances(bind, sql_rep_schema, mitm_data.header.mitm, instances)