diff --git a/python/gtsam/tests/test_ShonanAveraging.py b/python/gtsam/tests/test_ShonanAveraging.py
index fe0d7fc2b..a873a6430 100644
--- a/python/gtsam/tests/test_ShonanAveraging.py
+++ b/python/gtsam/tests/test_ShonanAveraging.py
@@ -13,6 +13,7 @@ Author: Frank Dellaert
 import unittest
 
 import gtsam
+import numpy as np
 from gtsam import (
     BetweenFactorPose2,
     LevenbergMarquardtParams,