contracts / kotlin.collections.Iterable

### Extensions for kotlin.collections.Iterable

sumCash | `fun Iterable<ContractState>.sumCash(): <ERROR CLASS>` Sums the cash states in the list, throwing an exception if there are none.
sumCashBy | `fun Iterable<ContractState>.sumCashBy(owner: PublicKey): <ERROR CLASS>` Sums the cash states in the list that are owned by the given key, throwing an exception if there are none.
sumCashOrNull | `fun Iterable<ContractState>.sumCashOrNull(): <ERROR CLASS>` Sums the cash states in the list, returning null if there are none.
sumCashOrZero | `fun Iterable<ContractState>.sumCashOrZero(currency: Currency): <ERROR CLASS>` Sums the cash states in the list, returning zero of the given currency if there are none.