@@ -9,7 +9,6 @@ import pickle

 import sys

 import time

 import traceback

-import types

 import warnings

 from contextlib import suppress

@@ -497,17 +496,16 @@ class AsyncRunner(BaseRunner):

                 return False

         if executor is None:

-            if isinstance(learner.function, types.LambdaType):

-                raise ValueError(

-                    "A lambda function cannot be pickled and "

-                    "therefore doesn't work with the default executor."

-                    "Either do not use a lamdba or use a framework that"

-                    " allows this, e.g. `ipyparallel` with `dill`."

-                )

             try:

                 pickle.dumps(learner.function)

             except pickle.PicklingError:

-                raise ValueError("`learner.function` needs to be pickleble.")

+                raise ValueError(

+                    "`learner.function` cannot be pickled (is it a lamdba function?)"

+                    " and therefore does not work with the default executor."

+                    " Either make sure the function is pickleble or use an executor"

+                    " that might work with 'hard to pickle'-functions"

+                    " , e.g. `ipyparallel` with `dill`."

+                )

         super().__init__(

             learner,