diff --git a/src/matchbox/common/results.py b/src/matchbox/common/results.py
index 3e853e7..ff97e5c 100644
--- a/src/matchbox/common/results.py
+++ b/src/matchbox/common/results.py
@@ -514,7 +514,7 @@ def diff(self) -> Iterator[tuple[set[T], set[T]]]:
 
 
 def component_to_hierarchy(
-    table: pa.Table, dtype: pa.DataType = pa.int32, salt: int | None = None
+    table: pa.Table, dtype: pa.DataType = pa.int32, salt: int = 1
 ) -> pa.Table:
     """
     Convert pairwise probabilities into a hierarchical representation.