void Book(MakeTransfer transfer)
=> accounts.Get(transfer.DebitedAccountId)
.Bind(account => account.Debit(transfer.Amount))
.ForEach(newState =>
{
accounts.Save(transfer.DebitedAccountId, newState);
swift.Wire(transfer, newState);
});
MakeTransfer Normalize(MakeTransfer request) => request; // remove whitespace, toUpper, etc.
public void MakeTransfer(MakeTransfer transfer) => Some(transfer) .Map(Normalize) .Where(validator.IsValid) .ForEach(Book);