diff --git a/asciimatics/utilities.py b/asciimatics/utilities.py
index <HASH>..<HASH> 100644
--- a/asciimatics/utilities.py
+++ b/asciimatics/utilities.py
@@ -52,7 +52,7 @@ class _DotDict(dict):
     __delattr__ = dict.__delitem__
 
 
-class BoxTool:
+class BoxTool(object):
     """Tool for building boxes out of characters. Supports a variety of line
     styles from `asciimatics.constants`:
Make BoxTool inherit from object so it works properly in Python <I>