diff --git a/src/_gettsim/functions/derived_function.py b/src/_gettsim/functions/derived_function.py
index 8a16228ad..c0a7f563c 100644
--- a/src/_gettsim/functions/derived_function.py
+++ b/src/_gettsim/functions/derived_function.py
@@ -7,6 +7,7 @@
 if TYPE_CHECKING:
     from collections.abc import Callable
 
+
 class DerivedFunction(PolicyFunction):
     """
     A function that is derived from other functions.