How to use the azure-mgmt-subscription.azure.mgmt.subscription.operations.subscriptions_operations.SubscriptionsOperations function in azure-mgmt-subscription

self, credentials, base_url=None):

        self.config = SubscriptionClientConfiguration(credentials, base_url)
        super(SubscriptionClient, self).__init__(self.config.credentials, self.config)

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

        self.operations = Operations(
            self._client, self.config, self._serialize, self._deserialize)
        self.subscription_operation = SubscriptionOperationOperations(
            self._client, self.config, self._serialize, self._deserialize)
        self.subscription_factory = SubscriptionFactoryOperations(
            self._client, self.config, self._serialize, self._deserialize)
        self.subscriptions = SubscriptionsOperations(
            self._client, self.config, self._serialize, self._deserialize)
        self.tenants = TenantsOperations(
            self._client, self.config, self._serialize, self._deserialize)