@Override
 public List<String> findUserIdsWithConnection(Connection<?> connection) {
   ConnectionKey key = connection.getKey();
   List<SocialUserConnection> socialUserConnections =
       socialUserConnectionRepository.findAllByProviderIdAndProviderUserId(
           key.getProviderId(), key.getProviderUserId());
   return socialUserConnections
       .stream()
       .map(SocialUserConnection::getUserId)
       .collect(Collectors.toList());
 };