diff --git a/beetsplug/replaygain.py b/beetsplug/replaygain.py
index da38251aa..87a4eb2dc 100644
--- a/beetsplug/replaygain.py
+++ b/beetsplug/replaygain.py
@@ -18,6 +18,7 @@ import os
 import collections
 import itertools
 import sys
+import warnings
 
 from beets import ui
 from beets.plugins import BeetsPlugin