diff --git a/data_structures/binary tree/AVLtree.py b/data_structures/binary tree/AVLtree.py
index 43fff9645..cd867906f 100644
--- a/data_structures/binary tree/AVLtree.py	
+++ b/data_structures/binary tree/AVLtree.py	
@@ -1,4 +1,7 @@
 # -*- coding: utf-8 -*-
+'''
+An auto-balanced binary tree!
+'''
 import math
 class my_queue:
     def __init__(self):