--- a/src/pyams_utils/interfaces/tree.py	Mon Dec 03 10:27:02 2018 +0100
+++ b/src/pyams_utils/interfaces/tree.py	Mon Dec 03 10:27:22 2018 +0100
@@ -13,18 +13,8 @@
 #
 ##############################################################################
 
-
-# import standard packages
-
-# import Zope3 interfaces
-
-# import local interfaces
-
-# import Zope3 packages
 from zope.interface import Interface, Attribute
 
-# import local packages
-
 
 class INode(Interface):
     """Tree node interface"""
@@ -35,6 +25,8 @@
 
     css_class = Attribute("Node's CSS class")
 
+    order = Attribute("Node's order")
+
     def get_level(self):
         """Get depth level of current node"""