- self.repr_traverse('', pointer_left, self.root.left, self.root.left is not None)
- self.repr_traverse('', pointer_right, self.root.right, False)
- return self.viz
+ ret += self.repr_traverse('', pointer_left, self.root.left, self.root.left is not None)
+ ret += self.repr_traverse('', pointer_right, self.root.right, False)
+ return ret