diff --git a/faiss/python/array_conversions.py b/faiss/python/array_conversions.py
index 82d5162941..0c57defe1e 100644
--- a/faiss/python/array_conversions.py
+++ b/faiss/python/array_conversions.py
@@ -10,6 +10,7 @@
 
 import numpy as np
 import array
+import warnings
 
 from faiss.loader import *