session.py 文件源码

def request(self, method, url, **kwargs):

        headers = kwargs.get('headers')
        if headers:
            headers = dict(headers)
            if 'User-Agent' not in map(str.title, headers.keys()):
                headers['User-Agent'] = self.user_agent
        else:
            headers = self.default_headers

        kwargs['headers'] = headers

        try:
            return super(RequestsSession, self).request(method, url, **kwargs)
        except requests.RequestException:
            raise RequestError