Subscriptions.update crashes

I am using Deepl translation.

I have just implemented and started the synchronization process of adding Subscription with reference to the above document,

Can only add, remove, or update subscriptions within a write subscription block.

error and the application crashed.
I tried to implement write as per the error and tried the following code.

try await subscriptions.write {
	if foundSubscription != nil {
		~~~
	}
}

If you do so
'write' has been renamed to 'update': SyncSubscriptionSet write is unavailable, please use .update instead.
error occurred.

I would like to know how to resolve this error and perform the synchronization process of adding Subscription.

Best regards.