diff --git a/crystal_toolkit/components/phonon.py b/crystal_toolkit/components/phonon.py
index 38e75878..4d28212c 100644
--- a/crystal_toolkit/components/phonon.py
+++ b/crystal_toolkit/components/phonon.py
@@ -174,7 +174,7 @@ def layout(self) -> html.Div:
 
     @staticmethod
     def _get_ph_bs_dos(
-        data: dict[str, Any] | None
+        data: dict[str, Any] | None,
     ) -> tuple[PhononBandStructureSymmLine, CompletePhononDos]:
         data = data or {}