code: public static Specification<JpaDistributionSetType> isDeleted(final Boolean isDeleted) {
          return (targetRoot, query, cb) -> cb.equal(targetRoot.<Boolean> get(JpaDistributionSetType_.deleted),
                  isDeleted);
      }
docs: {@link Specification} for retrieving {@link DistributionSetType}s by its
  DELETED attribute.
  
  @param isDeleted
  TRUE/FALSE are compared to the attribute DELETED. If NULL the
  attribute is ignored
  @return the {@link DistributionSetType} {@link Specification}