code: public Optional<SingularityRequestGroup> getRequestGroup(String requestGroupId) {
      final Function<String, String> requestUri = (host) -> String.format(REQUEST_GROUP_FORMAT, getApiBase(host), requestGroupId);
  
      return getSingle(requestUri, "request group", requestGroupId, SingularityRequestGroup.class);
    }
docs: Retrieve a specific request group by id
  
  @param requestGroupId
  The request group ID to search for
  
  @return
  A {@link SingularityRequestGroup}