code: public function getTypeAllowableValues()
      {
          return [
              self::TYPE_SEQUENTIAL,
              self::TYPE_EVALUATE,
              self::TYPE_SELECT,
              self::TYPE_PARALLEL,
              self::TYPE_PARALLEL_BY_EVALUATION,
              self::TYPE_SEC_JOIN,
              self::TYPE_DISCRIMINATOR,
          ];
      }
docs: Gets allowable values of the enum
  @return string[]