diff --git a/src/moscot/problems/cross_modality/_mixins.py b/src/moscot/problems/cross_modality/_mixins.py
index 18e896e5f..cc4079ab8 100644
--- a/src/moscot/problems/cross_modality/_mixins.py
+++ b/src/moscot/problems/cross_modality/_mixins.py
@@ -208,7 +208,7 @@ def annotation_mapping(  # type: ignore[misc]
             - ``'max'`` - pick the label of the annotated cell with the highest matching probability.
             - ``'sum'`` - aggregate the annotated cells by label then
               pick the label with the highest total matching probability.
-              
+
         annotation_label
             Key in :attr:`~anndata.AnnData.obs` where the annotation is stored.
         forward