diff --git a/pokemontools/crystal.py b/pokemontools/crystal.py
index e79cf6d..de0423d 100644
--- a/pokemontools/crystal.py
+++ b/pokemontools/crystal.py
@@ -1,5 +1,8 @@
 # -*- coding: utf-8 -*-
-# utilities to help disassemble pokémon crystal
+"""
+utilities to help disassemble pokémon crystal
+"""
+
 import os
 import sys
 import inspect