diff --git a/hugr-py/src/hugr/hugr.py b/hugr-py/src/hugr/hugr.py
index b4f70050a..619a09955 100644
--- a/hugr-py/src/hugr/hugr.py
+++ b/hugr-py/src/hugr/hugr.py
@@ -252,7 +252,7 @@ def _node_links(self, node: Node, links: dict[P, K]) -> Iterable[tuple[P, list[K
         try:
             direction = next(iter(links.keys())).direction
         except StopIteration:
-            return iter(())
+            return
         # iterate over known offsets
         for offset in range(self.num_ports(node, direction)):
             port = cast(P, node.port(offset, direction))