'Authenticates the session with DownloadStation'

def _get_auth(self):

    if (self.session.cookies and self.auth):
        return self.auth
    params = {u'api': u'SYNO.API.Auth', u'version': 2, u'method': u'login', u'account': (self.username.encode(u'utf-8') if isinstance(self.username, six.text_type) else self.username), u'passwd': (self.password.encode(u'utf-8') if isinstance(self.password, six.text_type) else self.password), u'session': u'DownloadStation', u'format': u'cookie'}
    self.response = self.session.get(self.urls[u'login'], params=params, verify=False)
    self.auth = self._check_response()
    return self.auth
