diff --git a/test/test_inference/test_signature.py b/test/test_inference/test_signature.py
index b97c1e90..f8f71581 100644
--- a/test/test_inference/test_signature.py
+++ b/test/test_inference/test_signature.py
@@ -1,5 +1,5 @@
 from textwrap import dedent
-from operator import ge
+from operator import ge, lt
 import re
 import os