diff --git a/tests/test_custom_functions.py b/tests/test_custom_functions.py
index 23c865a..9932908 100644
--- a/tests/test_custom_functions.py
+++ b/tests/test_custom_functions.py
@@ -9,6 +9,7 @@ class CustomFunctions(functions.Functions):
     def _func_length0(self, s):
         return 0 if s is None else len(s)
 
+
 class TestCustomFunctions(unittest.TestCase):
     def setUp(self):
         self.options = jmespath.Options(custom_functions=CustomFunctions())