diff --git a/docs/run_module.md b/docs/run_module.md
index 5aa4488..6f74490 100644
--- a/docs/run_module.md
+++ b/docs/run_module.md
@@ -4,6 +4,7 @@ The run module is arguably the most important part of the *alma* interface. It i
 
 ```python
 import random
+import os
 
 def run(instance, save, state):
     lines = open(instance).readlines()