diff --git a/experiments/datascope/experiments/scenarios/base.py b/experiments/datascope/experiments/scenarios/base.py
index 7883f32..6d9ba92 100644
--- a/experiments/datascope/experiments/scenarios/base.py
+++ b/experiments/datascope/experiments/scenarios/base.py
@@ -1296,7 +1296,7 @@ def get_instances(
             else:
                 # Find distinct grouping attribute assignments.
                 all_values: List[Tuple] = []
-                partitioned = study.dataframe.groupby(partby)
+                partitioned = study.dataframe.groupby(partby)  # type: ignore
                 if len(study.scenarios) > 0:
                     all_values = list(partitioned.groups.keys())