Merge pull request #398 from ankostis/singleton_errlog

feat(conf): explain which singleton is already instanciated
ipython · May 3, 2017 · 3d41bb7 · 3d41bb7
2 parents 0aa4350 + c027b51
commit 3d41bb7
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/traitlets/config/configurable.py b/traitlets/config/configurable.py
@@ -505,8 +505,8 @@ def instance(cls, *args, **kwargs):
             return cls._instance
         else:
             raise MultipleInstanceError(
-                'Multiple incompatible subclass instances of '
-                '%s are being created.' % cls.__name__
+                "An incompatible sibling of '%s' is already instanciated"
+                " as singleton: %s" % (cls.__name__, type(cls._instance).__name__)
             )
 
     @classmethod