How to use the datacite.DataCiteMDSClient function in datacite

def __init__(self, base_url, prefix, client=None):
        self.base_url = base_url
        self.prefix = prefix
        self._client = client or DataCiteMDSClient(
            url=self.base_url,
            username=settings.DATACITE_USERNAME,
            password=settings.DATACITE_PASSWORD,
            prefix=self.prefix
        )

def __init__(self, base_url, prefix, client=None):
        self.base_url = base_url
        self.prefix = prefix
        self._client = client or DataCiteMDSClient(
            url=self.base_url,
            username=settings.DATACITE_USERNAME,
            password=settings.DATACITE_PASSWORD,
            prefix=self.prefix
        )

def __init__(self):
        """Initialize provider."""
        self.api = DataCiteMDSClient(
            username=cfg.get('CFG_DATACITE_USERNAME'),
            password=cfg.get('CFG_DATACITE_PASSWORD'),
            prefix=cfg.get('CFG_DATACITE_DOI_PREFIX'),
            test_mode=cfg.get('CFG_DATACITE_TESTMODE', False),
            url=cfg.get('CFG_DATACITE_URL')
        )