Bella enzo

    def node_level(self, p):
        node = self._validate(p)
        if (node == self._root):
            return 1
        else:
            return 1 + self.node_level(node._parent)

    def print_sub_tree(self, children):
        for x in children:
            print("-  " * self.node_level(x), x._node._label, '\t'*(10-self.node_level(x)), '->  | depth: ',x._node._depth, '  | mark: ',x._node._mark, '  | element: ',x._node._element)
            if not (self.is_leaf(x)):
                self.print_sub_tree(x._node._children)

    def visualize(self, root):
        print('- ', root._node._label)
        self.print_sub_tree(root._node._children)