Same as here maybe?: Tackling CertifiedData in Motoko - #18 by skilesare
Bucket.doAThing(witnessContainingLeafsWithAllSwarmNodesAndParentAndTimeStamp, certificate, myParams)
Swarm Node:
public func doAThing(witness: Witness, cert : CandidVersionOfCertificate, myParams: MyParams){
assert(verifySiblingsAndTimeStamp(cert, witness)); //does this need to get the shared BLS key via a system function?
//trust below code
}