diff --git a/examples/python/graphs/graphs.py b/examples/python/graphs/graphs.py
index 4c3e0cd26f75..3bf490c625d9 100644
--- a/examples/python/graphs/graphs.py
+++ b/examples/python/graphs/graphs.py
@@ -45,7 +45,7 @@
 random.seed(42)
 
 
-def log_lattice(num_nodes) -> None:
+def log_lattice(num_nodes: int) -> None:
     coordinates = itertools.product(range(num_nodes), range(num_nodes))
 
     nodes, colors = zip(*[