/**
  * @param ProfessionZeroLevel $zeroLevel
  * @param ProfessionFirstLevel $firstLevel
  *
  * @return ProfessionLevels
  */
 private function createProfessionLevelsWith(ProfessionZeroLevel $zeroLevel, ProfessionFirstLevel $firstLevel)
 {
     $professionLevels = new ProfessionLevels($zeroLevel, $firstLevel);
     self::assertSame($firstLevel, $professionLevels->getFirstLevel());
     self::assertEquals([$zeroLevel, $firstLevel], $professionLevels->getSortedProfessionLevels());
     return $professionLevels;
 }