if(!instrument.isOperator(Util.USER_FROM_ID.apply(actor))) {
throw new AccessDenied("User is not an operator of instrument");
}
Set<PendingOperator> pendingOperators = instrument.getPending();
if(pendingOperators.size() == 0) {
throw new ObjectNotFoundException();
}
final PendingOperator pending = find(pendingOperators, new Predicate<PendingOperator>() {
@Override
public boolean apply(PendingOperator pendingOperator) {
return pendingOperator.getUser().equals(user);