diff --git a/src/cogent3/core/alignment.py b/src/cogent3/core/alignment.py
index 247ec1dff..11e9bfd76 100644
--- a/src/cogent3/core/alignment.py
+++ b/src/cogent3/core/alignment.py
@@ -2615,7 +2615,9 @@ def __repr__(self):
             seqs.append(f"{name}[{delimiter.join(elts)}]")
         seqs = ", ".join(seqs)
 
-        return f"{len(self.names)} x {self.seq_len} {self.moltype.label} alignment: {seqs}"
+        return (
+            f"{len(self.names)} x {self.seq_len} {self.moltype.label} alignment: {seqs}"
+        )
 
     def alignment_quality(self, app_name: str = "ic_score", **kwargs):
         """