Isn't this just in-order traversal... class Linked: def __init__(self, data, left=None, right=None): self.data = data self.

Isn't this just in-order traversal... class Linked: def __init__(self, data, left=None, right=None): self.data = data self.left = left self.right = right def tree_to_list(self): if self.left is not None: first, left = self.left.tree_to_list() left.right = self self.left = left else: first = self if self.right is not None: right, last = self.right.tree_to_list() right.left = self self.right = right else: last = self first.left = last last.right = first return first, last