如何将霍夫曼编码的字符写入文件？

import heapq
import os

# 定义霍夫曼树节点类
class HuffmanNode:
    def __init__(self, char, freq):
        self.char = char
        self.freq = freq
        self.left = None
        self.right = None

    def __lt__(self, other):
        return self.freq < other.freq

# 构建霍夫曼树
def build_huffman_tree(text):
    # 统计字符频率
    freq_dict = {}
    for char in text:
        freq_dict[char] = freq_dict.get(char, 0) + 1

    # 构建霍夫曼树
    heap = []
    for char, freq in freq_dict.items():
        heapq.heappush(heap, HuffmanNode(char, freq))

    while len(heap) > 1:
        node1 = heapq.heappop(heap)
        node2 = heapq.heappop(heap)
        merged = HuffmanNode(None, node1.freq + node2.freq)
        merged.left = node1
        merged.right = node2
        heapq.heappush(heap, merged)

    return heapq.heappop(heap)

# 生成编码表
def generate_huffman_code_table(node, code, code_table):
    if node is None:
        return

    if node.char is not None:
        code_table[node.char] = code
        return

    generate_huffman_code_table(node.left, code + "0", code_table)
    generate_huffman_code_table(node.right, code + "1", code_table)

# 将霍夫曼编码写入文件
def write_huffman_code_to_file(text, code_table, output_file):
    with open(output_file, "wb") as f:
        # 写入编码表
        for char, code in code_table.items():
            f.write(char.encode("utf-8"))
            f.write(code.encode("utf-8"))

        # 写入编码后的文本
        encoded_text = "".join(code_table[char] for char in text)
        padded_encoded_text = pad_encoded_text(encoded_text)
        b = bytearray()
        for i in range(0, len(padded_encoded_text), 8):
            byte = padded_encoded_text[i:i + 8]
            b.append(int(byte, 2))
        f.write(bytes(b))

# 补齐编码后的文本长度为8的倍数
def pad_encoded_text(encoded_text):
    extra_padding = 8 - len(encoded_text) % 8
    for i in range(extra_padding):
        encoded_text += "0"
    padding_info = "{0:08b}".format(extra_padding)
    encoded_text = padding_info + encoded_text
    return encoded_text

# 示例使用
text = "hello world!"
huffman_tree = build_huffman_tree(text)
code_table = {}
generate_huffman_code_table(huffman_tree, "", code_table)
write_huffman_code_to_file(text, code_table, "compressed_file.bin")