diff --git a/skgstat/tests/test_variogram.py b/skgstat/tests/test_variogram.py
index 18f2ab0..ef10141 100644
--- a/skgstat/tests/test_variogram.py
+++ b/skgstat/tests/test_variogram.py
@@ -1656,7 +1656,7 @@ def test_cross_variogram_warns(self):
         if GSTOOLS_AVAILABLE:
             with self.assertWarns(Warning) as w:
                 vario.to_gstools()
-        
+
             self.assertTrue("This instance is a cross-variogram!!" in str(w.warning))