Gets client credentials access token

def _request_access_token(self):
        """Gets client credentials access token """
        payload = {'grant_type': 'authorization_code',
                   'code': code,
                   'redirect_uri': self.redirect_uri}

        headers = _make_authorization_headers(self.client_id,
                                              self.client_secret)

        response = requests.post(self.OAUTH_TOKEN_URL, data=payload,
                                 headers=headers,
                                 verify=LOGIN_VERIFY_SSL_CERT)

        if response.status_code is not 200:
            raise MercedesMeAuthError(response.reason)
        token_info = response.json()
        return token_info