Function libpijul::change::dependencies

pub fn dependencies<'a, Local: 'a, I: Iterator<Item = &'a Hunk<Option<Hash>, Local>>, T: ChannelTxnT + DepsTxnT<DepsError = <T as GraphTxnT>::GraphError>>(
    txn: &T, 
    channel: &T::Channel, 
    changes: I
) -> Result<(Vec<Hash>, Vec<Hash>), TxnErr<T::DepsError>>