diff --git a/tiramisu/config.py b/tiramisu/config.py
index 6d261be..d255bf3 100644
--- a/tiramisu/config.py
+++ b/tiramisu/config.py
@@ -31,8 +31,7 @@ from tiramisu.value import Values
 
 class SubConfig(object):
     "sub configuration management entry"
-    __slots__ = ('_cfgimpl_descr', '_cfgimpl_subconfigs', '_cfgimpl_parent',
-                 '_cfgimpl_context')
+    __slots__ = ('_cfgimpl_descr', '_cfgimpl_parent', '_cfgimpl_context')
 
     def __init__(self, descr, parent, context):  # FIXME , slots):
         """ Configuration option management master class
@@ -47,7 +46,6 @@ class SubConfig(object):
         # main option description
         self._cfgimpl_descr = descr
         # sub option descriptions
-        self._cfgimpl_subconfigs = None
         self._cfgimpl_parent = parent
         self._cfgimpl_context = context
         #self._cfgimpl_build(slots)