Improve error message in ListTransformer when not passing a list (fly…

…teorg#1882) Signed-off-by: Fabio Grätz <[email protected]> Co-authored-by: Fabio Grätz <[email protected]>
troychiu · Oct 10, 2023 · 3afcbb4 · 3afcbb4
1 parent 8cf2e0b
commit 3afcbb4
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/flytekit/core/type_engine.py b/flytekit/core/type_engine.py
@@ -1141,7 +1141,12 @@ def to_python_value(self, ctx: FlyteContext, lv: Literal, expected_python_type:
         try:
             lits = lv.collection.literals
         except AttributeError:
-            raise TypeTransformerFailedError()
+            raise TypeTransformerFailedError(
+                (
+                    f"The expected python type is '{expected_python_type}' but the received Flyte literal value "
+                    f"is not a collection (Flyte's representation of Python lists)."
+                )
+            )
         if self.is_batchable(expected_python_type):
             from flytekit.types.pickle import FlytePickle