Login v2ex, otherwise we can't complete the mission.

def login(self):
        """Login v2ex, otherwise we can't complete the mission."""
        response = self.session.get(self.signin_url, verify=False)
        user_param, password_param = self._get_hashed_params(response.text)
        login_data = {
            user_param: self.config['username'],
            password_param: self.config['password'],
            'once': self._get_once(response.text),
            'next': '/'
        }
        headers = {'Referer': 'https://www.v2ex.com/signin'}
        self.session.post(self.signin_url, headers=headers, data=login_data)