@Override
    public boolean apply(ValueAttribute input) {
      return input.isGenerateDerived;
    }
Predicate on instance of DiscoveredAttribute that evaluates attribute isGenerateDerived.
@return predicate on DiscoveredAttribute evaluates to 'isGenerateDerived' attribute
value-processor/src/org/immutables/value/processor/meta/ValueAttributeFunctions.java