diff --git a/coding_test/leetcode/binary_tree_paths/test.py b/coding_test/leetcode/binary_tree_paths/test.py
index cbf08fb..889e660 100644
--- a/coding_test/leetcode/binary_tree_paths/test.py
+++ b/coding_test/leetcode/binary_tree_paths/test.py
@@ -28,7 +28,8 @@ def backtrack(node: TreeNode):
                 backtrack(node.right)
                 stack.pop()
 
-        backtrack(root)
+        if root is not None:
+            backtrack(root)
         return result