diff --git a/hlink/tests/core/classifier_test.py b/hlink/tests/core/classifier_test.py
index 1010262..4ffa37a 100644
--- a/hlink/tests/core/classifier_test.py
+++ b/hlink/tests/core/classifier_test.py
@@ -9,6 +9,7 @@
 else:
     xgboost_available = True
 
+
 @pytest.mark.skipif(not xgboost_available, reason="requires the xgboost library")
 def test_choose_classifier_supports_xgboost():
     """