diff --git a/stix2/test/v21/test_timestamp_precision.py b/stix2/test/v21/test_timestamp_precision.py
index be07f1b..8cb9735 100644
--- a/stix2/test/v21/test_timestamp_precision.py
+++ b/stix2/test/v21/test_timestamp_precision.py
@@ -1,7 +1,7 @@
 import datetime
+import sys
 
 import pytest
-import sys
 
 import stix2
 from stix2.utils import (