diff --git a/openml/evaluations/functions.py b/openml/evaluations/functions.py
index 7747294d7..2534bb230 100644
--- a/openml/evaluations/functions.py
+++ b/openml/evaluations/functions.py
@@ -231,9 +231,10 @@ def __list_evaluations(api_call: str) -> list[OpenMLEvaluation]:
             "Error in return XML, does not contain " f'"oml:evaluations": {evals_dict!s}',
         )
 
-    assert isinstance(evals_dict["oml:evaluations"]["oml:evaluation"], list), type(
-        evals_dict["oml:evaluations"],
-    )
+    assert isinstance(
+        evals_dict["oml:evaluations"]["oml:evaluation"], list
+    ), "Expected 'oml:evaluation' to be a list, but got"
+    f"{type(evals_dict['oml:evaluations']['oml:evaluation']).__name__}. "
 
     uploader_ids = list(
         {eval_["oml:uploader"] for eval_ in evals_dict["oml:evaluations"]["oml:evaluation"]},