diff --git a/xbob/learn/activation/__init__.py b/xbob/learn/activation/__init__.py
index b66dfe3cedc055640aa600c1144610f7baa25a4d..05534bd471f8685d1f9abd3e4b1ed2e1f0bcc9a9 100644
--- a/xbob/learn/activation/__init__.py
+++ b/xbob/learn/activation/__init__.py
@@ -7,5 +7,4 @@ def get_include():
   return __import__('pkg_resources').resource_filename(__name__, 'include')
 
 # gets sphinx autodoc done right - don't remove it
-__all__ = [k for k in dir() if not k.startswith('_')]
-del k
+__all__ = [_ for _ in dir() if not _.startswith('_')]