diff --git a/edbob/core.py b/edbob/core.py
index 553ddab..70ebc79 100644
--- a/edbob/core.py
+++ b/edbob/core.py
@@ -112,7 +112,7 @@ def graft(target, source, names=None):
         if hasattr(source, '__all__'):
             names = source.__all__
         else:
-            names = dir(source)
+            names = [x for x in dir(source) if not x.startswith('_')]
     elif isinstance(names, basestring):
         names = [names]