如何在python中打印树形结构的Trie？

class TrieNode:
    def __init__(self):
        self.children = {}
        self.is_end_of_word = False

def insert(root, word):
    node = root
    for char in word:
        if char not in node.children:
            node.children[char] = TrieNode()
        node = node.children[char]
    node.is_end_of_word = True

def print_trie(node, prefix):
    if node.is_end_of_word:
        print(prefix)
    for char, child in node.children.items():
        print_trie(child, prefix + char)

# 创建一个空的Trie树
root = TrieNode()

# 插入一些单词
insert(root, "apple")
insert(root, "banana")
insert(root, "application")
insert(root, "book")

# 打印树形结构的Trie
print_trie(root, "")