diff --git a/trees/bt_height.py b/trees/bt_height.py
index bb16d53..32fbc7d 100644
--- a/trees/bt_height.py
+++ b/trees/bt_height.py
@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 # author: bt3gl
 
+
 def height(root):
       
       if not root: