Binary Right Side View

class Solution:
    def rightSideView(self, root: Optional[TreeNode]) -> List[int]:

        levelmap = {}

        def helper(root, level=0):
            if not root:
                return

            if level not in levelmap:
                levelmap[level] = root.val

            helper(root.right, level=level+1)
            helper(root.left, level=level+1)

            return

        helper(root, 0)

        return list(levelmap.values())