Python Scrapy -在爬行器退出后执行代码

from scrapy import signals
from scrapy.exceptions import NotConfigured

class MySpiderClosedExtension:
    def __init__(self, my_param):
        self.my_param = my_param

    @classmethod
    def from_crawler(cls, crawler):
        if not crawler.settings.getbool('MY_EXTENSION_ENABLED'):
            raise NotConfigured

        my_param = crawler.settings.get('MY_PARAM')
        ext = cls(my_param)

        crawler.signals.connect(ext.spider_closed, signal=signals.spider_closed)

        return ext

    def spider_closed(self, spider):
        # 在这里编写需要执行的代码
        print("Spider closed. My parameter: ", self.my_param)

EXTENSIONS = {
    'myproject.extensions.MySpiderClosedExtension': 500,
}

MY_EXTENSION_ENABLED = True
MY_PARAM = "example_parameter"