diff --git a/src/fimdlp/mdlp.py b/src/fimdlp/mdlp.py
index 0378ebf..2a2114a 100644
--- a/src/fimdlp/mdlp.py
+++ b/src/fimdlp/mdlp.py
@@ -151,7 +151,8 @@ class FImdlp(TransformerMixin, BaseEstimator):
         )
         return result
 
-    def factorize(self, yy):
+    @staticmethod
+    def factorize(yy):
         """Factorize the input labels
 
         Parameters
diff --git a/src/fimdlp/tests/FImdlp_test.py b/src/fimdlp/tests/FImdlp_test.py
index fcfd888..068a4e8 100644
--- a/src/fimdlp/tests/FImdlp_test.py
+++ b/src/fimdlp/tests/FImdlp_test.py
@@ -205,7 +205,8 @@ class FImdlpTest(unittest.TestCase):
         computed = clf.factorize(y)
         self.assertListEqual([0, 1, 1, 2, 3], computed)
 
-    def test_sklearn_transformer(self):
+    @staticmethod
+    def test_sklearn_transformer():
         for check, test in check_estimator(FImdlp(), generate_only=True):
             test(check)