code: public static Specification<JpaDistributionSet> isCompleted(final Boolean isCompleted) {
          return (targetRoot, query, cb) -> cb.equal(targetRoot.<Boolean> get(JpaDistributionSet_.complete), isCompleted);
  
      }
docs: {@link Specification} for retrieving {@link DistributionSet}s by its
  COMPLETED attribute.
  
  @param isCompleted
  TRUE/FALSE are compared to the attribute COMPLETED. If NULL
  the attribute is ignored
  @return the {@link DistributionSet} {@link Specification}