diff --git a/astartes/samplers/extrapolation/scaffold.py b/astartes/samplers/extrapolation/scaffold.py
index 148f362..da29b4a 100644
--- a/astartes/samplers/extrapolation/scaffold.py
+++ b/astartes/samplers/extrapolation/scaffold.py
@@ -42,7 +42,8 @@ def _sample(self):
         for cluster_id, (scaffold, indices) in enumerate(scaffold_to_indices.items()):
             if scaffold == "":
                 warnings.warn(
-                    f"No matching scaffold was found for the {len(indices)} " f"molecules corresponding to indices {indices}",
+                    f"No matching scaffold was found for the {len(indices)} " 
+                    f"molecules corresponding to indices {indices}",
                     NoMatchingScaffold,
                 )
             for idx in indices: