diff --git a/notes-and-examples/2026.05.13/homework.py b/notes-and-examples/2026.05.13/homework.py
index 5035c17..fe98b67 100644
--- a/notes-and-examples/2026.05.13/homework.py
+++ b/notes-and-examples/2026.05.13/homework.py
@@ -116,6 +116,7 @@ print("================ Searches ================")
 # is the search result giving us the expected node?
 print(test_tree.search(4) == test_tree.root.left.right)
 print(test_tree.search(6) == test_tree.root.right)
+print(test_tree.search(20) is None)
 
 print("================ Removals ================")