code: public function lookup($hash, $className = 'Orkestra\Bundle\ApplicationBundle\Entity\User')
      {
          try {
              return $this->hashedEntityHelper->lookup($hash, $className);
              
          } catch (\RuntimeException $e) {
              return null;
          }
      }
docs: Looks up a user with the given hash
  
  @param string $hash
  @param string $className
  @return null|HashedEntity