diff --git a/neuraxle/__init__.py b/neuraxle/__init__.py
index 3d187266..dd9b22cc 100644
--- a/neuraxle/__init__.py
+++ b/neuraxle/__init__.py
@@ -1 +1 @@
-__version__ = "0.5.0"
+__version__ = "0.5.1"
diff --git a/neuraxle/base.py b/neuraxle/base.py
index 1ab5d538..986e7379 100644
--- a/neuraxle/base.py
+++ b/neuraxle/base.py
@@ -1849,7 +1849,7 @@ def mutate(self, new_method="inverse_transform", method_to_assign_to="transform"
         except AttributeError as e:
             if warn:
                 import warnings
-                warnings.warn(e)
+                warnings.warn(repr(e))
 
         return new_base_step