Function sc_consensus_babe::authorship::claim_slot_using_keys

pub fn claim_slot_using_keys(
    slot: Slot, 
    epoch: &Epoch, 
    keystore: &SyncCryptoStorePtr, 
    keys: &[(AuthorityId, usize)]
) -> Option<(PreDigest, AuthorityId)>

Like claim_slot, but allows passing an explicit set of key pairs. Useful if we intend to make repeated calls for different slots using the same key pairs.