diff --git a/.gitignore b/.gitignore
index d22cf14..c48340c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 .idea/
-.claude
\ No newline at end of file
+.claude
+__pycache__/
+*.pyc
\ No newline at end of file
diff --git a/problems/medium/clone_graph_133/test_solution.py b/problems/medium/clone_graph_133/test_solution.py
index 78a5c03..add9a63 100644
--- a/problems/medium/clone_graph_133/test_solution.py
+++ b/problems/medium/clone_graph_133/test_solution.py
@@ -22,6 +22,8 @@ def verify_nodes(orig, cln):
 
             # Avoid infinite loops
             if orig in visited_orig:
+                # If we've seen this original node, we should have seen the clone too
+                assert cln in visited_clone
                 return
             visited_orig.add(orig)
             visited_clone.add(cln)