code: public function reverseTransform($id)
      {
          if (!$id) {
              return null;
          }
  
          $issue = $this->om
              ->getRepository('ChillPersonBundle:Person')
              ->findOneBy(array('id' => $id))
          ;
  
          if (null === $issue) {
              throw new TransformationFailedException(sprintf(
                  'An issue with id "%s" does not exist!',
                  $id
              ));
          }
  
          return $issue;
      }
docs: Transforms a string (id) to an object (issue).
  
  @param  string $id
  
  @return Issue|null
  
  @throws TransformationFailedException if object (issue) is not found.