--- a/ConfigTreeNode.py	Fri Sep 22 20:12:22 2017 +0300
+++ b/ConfigTreeNode.py	Thu Sep 28 12:20:40 2017 +0300
@@ -58,7 +58,7 @@
 XSDSchemaErrorMessage = _("{a1} XML file doesn't follow XSD schema at line {a2}:\n{a3}")
 
 
-class ConfigTreeNode:
+class ConfigTreeNode(object):
     """
     This class is the one that define confnodes.
     """