问Scrapy:将response.body保存为html文件？

EN

class ExampleSpider(scrapy.Spider):
    name = "example"
    allowed_domains = ['google.com']
    start_urls = ['http://google.com/']

    def __init__(self):
        self.path_to_html = html_path + 'index.html'
        self.path_to_header = header_path + 'index.html'
        self.html_file = open(self.path_to_html, 'w')

    def parse(self, response):
        url = response.url
        self.html_file.write(response.body)
        self.html_file.close()
        yield {
            'url': url
        }

Traceback (most recent call last):
  File "c:\python\python36-32\lib\site-packages\twisted\internet\defer.py", line
 653, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "c:\Users\kv\AtomProjects\example_project\example_bot\example_bot\spiders
\example.py", line 35, in parse
    self.html_file.write(response.body)
TypeError: write() argument must be str, not bytes