如何打印出三叉树？

class TreeNode:
    def __init__(self, value):
        self.value = value
        self.children = []

def print_tritree(root, level=0):
    if root is None:
        return
    
    # 打印当前节点的值
    print("  " * level + str(root.value))
    
    # 递归打印子节点
    for child in root.children:
        print_tritree(child, level + 1)

# 创建一个三叉树的示例
root = TreeNode(1)
node2 = TreeNode(2)
node3 = TreeNode(3)
node4 = TreeNode(4)
node5 = TreeNode(5)
node6 = TreeNode(6)

root.children = [node2, node3, node4]
node2.children = [node5]
node3.children = [node6]

# 打印三叉树
print_tritree(root)

1
  2
    5
  3
  4
    6