How to use the azure-cognitiveservices-search-customsearch.azure.cognitiveservices.search.customsearch.custom_search_client.CustomSearchClient function in azure-cognitiveservices-search-customsearch

def __init__(
            self, credentials, base_url=None):

        self.config = CustomSearchClientConfiguration(credentials, base_url)
        super(CustomSearchClient, self).__init__(self.config.credentials, self.config)

        client_models = {k: v for k, v in models.__dict__.items() if isinstance(v, type)}
        self.api_version = '1.0'
        self._serialize = Serializer(client_models)
        self._deserialize = Deserializer(client_models)

        self.custom_instance = CustomInstanceOperations(
            self._client, self.config, self._serialize, self._deserialize)