How to use the aliyun-python-sdk-core-v3.aliyunsdkcore.auth.Signer.Signer function in aliyun-python-sdk-core-v3

raise exceptions.ClientException(error_code.SDK_INVALID_CREDENTIAL,
                                             error_msg.get_msg('SDK_INVALID_CREDENTIAL'))


class SignerV1(Signer):
    def __init__(self, access_key, access_secret):
        self._access_key = access_key
        self._access_secret = access_secret

    def sign(self, region_id, request):
        header = request.get_signed_header(region_id, self._access_key, self._access_secret)
        url = request.get_url(region_id, self._access_key, self._access_secret)
        return header, url


class SignerV2(Signer):
    _MIN_SESSION_PERIOD = 900
    _MAX_SESSION_PERIOD = 3600
    _RETRY_DELAY_FAST = 3
    _PRIORITY = 1

    def __init__(self, public_key_id, private_key, session_period, region_id, debug=False):
        if not debug and session_period < self._MIN_SESSION_PERIOD or session_period > self._MAX_SESSION_PERIOD:
            raise exceptions.ClientException(
                error_code.SDK_INVALID_SESSION_EXPIRATION,
                error_msg.get_msg('SDK_INVALID_SESSION_EXPIRATION').format(self._MIN_SESSION_PERIOD,
                                                                           self._MAX_SESSION_PERIOD))

        self._public_key_id = public_key_id
        self._private_key = private_key
        self._session_period = session_period
        self._schedule_interval = session_period if debug else max(session_period * 0.8, 5)

def sign(self, region_id, request):
        pass

    @staticmethod
    def get_signer(credential, debug=False):
        if credential['ak'] is not None and credential['secret'] is not None:
            return SignerV1(credential['ak'], credential['secret'])
        elif credential['public_key_id'] is not None and credential['private_key'] is not None:
            return SignerV2(credential['public_key_id'], credential['private_key'], credential['session_period'],
                            credential['region_id'], debug)
        else:
            raise exceptions.ClientException(error_code.SDK_INVALID_CREDENTIAL,
                                             error_msg.get_msg('SDK_INVALID_CREDENTIAL'))


class SignerV1(Signer):
    def __init__(self, access_key, access_secret):
        self._access_key = access_key
        self._access_secret = access_secret

    def sign(self, region_id, request):
        header = request.get_signed_header(region_id, self._access_key, self._access_secret)
        url = request.get_url(region_id, self._access_key, self._access_secret)
        return header, url


class SignerV2(Signer):
    _MIN_SESSION_PERIOD = 900
    _MAX_SESSION_PERIOD = 3600
    _RETRY_DELAY_FAST = 3
    _PRIORITY = 1