code: @Override
      public ListUserHierarchyGroupsResult listUserHierarchyGroups(ListUserHierarchyGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeListUserHierarchyGroups(request);
      }
docs: <p>
  Returns a <code>UserHierarchyGroupSummaryList</code>, which is an array of <code>HierarchyGroupSummary</code>
  objects that contain information about the hierarchy groups in your instance.
  </p>
  
  @param listUserHierarchyGroupsRequest
  @return Result of the ListUserHierarchyGroups operation returned by the service.
  @throws InvalidRequestException
  The request is not valid.
  @throws InvalidParameterException
  One or more of the parameters provided to the operation are not valid.
  @throws ResourceNotFoundException
  The specified resource was not found.
  @throws ThrottlingException
  The throttling limit has been exceeded.
  @throws InternalServiceException
  Request processing failed due to an error or failure with the service.
  @sample AmazonConnect.ListUserHierarchyGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/connect-2017-08-08/ListUserHierarchyGroups"
  target="_top">AWS API Documentation</a>