/**
  * searchMember
  *
  * @param MemberRepositoryInterface $memberRepo
  * @param null                      $keyword
  *
  * @return \Xpressengine\Presenter\RendererInterface
  */
 public function searchMember(MemberRepositoryInterface $memberRepo, $keyword = null)
 {
     if ($keyword === null) {
         return Presenter::makeApi($memberRepo->all());
     }
     $matchedMemberList = $memberRepo->search(['displayName' => $keyword])->items();
     return Presenter::makeApi($matchedMemberList);
 }