def update(self, api_key=None, stripe_account=None, **kwargs):
        """
        Updates an existing subscription schedule
        and returns the updated SubscriptionSchedule.
        :param api_key: The api key to use for this request.
            Defaults to djstripe_settings.STRIPE_SECRET_KEY.
        :type api_key: string
        :param stripe_account: The optional connected account \
            for which this request is being made.
        :type stripe_account: string
        """
        stripe_subscription_schedule = self._api_update(
            api_key=api_key, stripe_account=stripe_account, **kwargs
        )
        return SubscriptionSchedule.sync_from_stripe_data(stripe_subscription_schedule)

        Updates an existing subscription schedule
        and returns the updated SubscriptionSchedule.
        :param api_key: The api key to use for this request.
            Defaults to djstripe_settings.STRIPE_SECRET_KEY.
        :type api_key: string
        :param stripe_account: The optional connected account             for which this request is being made.
        :type stripe_account: string
        
djstripe/models/billing.py