public bool Save(BankAccount bankAccount)
{
var eventStreamId = GetEventStreamId(bankAccount.Id);
var expectedVersion = bankAccount.StoredEventVersion == 0
? Option.None <int>()
: Option.Some(bankAccount.StoredEventVersion);
var accountSaved = _appendOnlyStore.AppendToStream(eventStreamId, bankAccount.Changes, expectedVersion);
return(accountSaved);
}