@Override
    public String toString() {
      return ValueAttributeFunctions.class.getSimpleName() + ".isGenerateAbstract()";
    }
Predicate on instance of DiscoveredAttribute that evaluates attribute isGenerateAbstract.
@return predicate on DiscoveredAttribute evaluates to 'isGenerateAbstract' attribute
value-processor/src/org/immutables/value/processor/meta/ValueAttributeFunctions.java