Joomla example load second model into view

<?php
/**
 * @version     $Id$
 * @package     com_cn_reports
 * @copyright   Copyright (C) 2015. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 * @author
 */
 // No direct access
defined('_JEXEC') or die;

jimport('joomla.application.component.view');
JLoader::register('Cn_reportsDateHelper', JPATH_COMPONENT_ADMINISTRATOR .'/helpers/cn_reportsdatehelper.php');

/**
 * View class for a list of Cn_reports.
 */
class Cn_reportsViewArchivecommissionsales extends JViewLegacy
{
    protected $items;
    protected $pagination;
    protected $state;

     /**
     * Display the view
     */
    public function display($tpl = null) {
        $this->state = $this->get('State');
        $this->items = $this->get('Items');
        $this->pagination = $this->get('Pagination');


        // Check for errors.
        if (count($errors = $this->get('Errors'))) {
            throw new Exception(implode("\n", $errors));
        }

        Cn_reportsHelper::addSubmenu('archivecommissionsales');

        // assign the server timezone as object
        $jtz = Cn_reportsDateHelper::getTimeZone();
        $this->assignRef('serverTz', $jtz);

       // Load second Model Named Cn_reportsModelArchivecommission
        $aModel = JModelLegacy::getInstance('Archivecommission', 'Cn_reportsModel');
        // load current state into model
        foreach ($this->state as $key => $value) {
            $aModel->setState($key,$value);
        }
        // assigne the model nto a referecne to us in other parts of the view
        $this->assignRef('archiveModel', $aModel);

        $this->addToolbar();

        $this->sidebar = JHtmlSidebar::render();
        parent::display($tpl);
    }

    /**
     * Add the page title and toolbar.
     *
     * @since   1.6
     */
    protected function addToolbar() {
        //TODO: Confirm Security on backend view.html.php in administrator/com_cn_reports/view/archivecommissionsales\view.html.php addToolbar() method
        JLoader::register('Cn_reportsHelper', JPATH_COMPONENT_ADMINISTRATOR .'/helpers/cn_reportshelper.php');
        $state = $this->get('State');
        $canDo = Cn_reportsHelper::getActions();

        JToolBarHelper::title(JText::_('COM_CN_REPORTS_TITLE_ARCHIVECOMMISSIONSALE'), 'rtreports.png');

        if ($canDo->get('core.admin')) {
            JToolBarHelper::preferences('com_cn_reports');
        }
         //Set sidebar action - New in 3.0
        JHtmlSidebar::setAction('index.php?option=com_cn_reports&view=archivecommissionsales');

        $this->extra_sidebar = '';

        //TODO: Add any filter custom Filters here. See: http://pastebin.com/w4CAhpgQ for example
    }
    /**
     * Gets the sort fields used in the display and for possible filters
     * @return multitype:string associative array with key of field and value from en-GB.com_cn_reports.ini file
     */
    protected function getSortFields()
    {
        // this array will show in the order created int he drop down coloum list.
        return array(
            'arc.id' => JText::_('JGRID_HEADING_ID'),
            'arc.order_id' => JText::_('COM_CN_REPORTS_FORM_LBL_ORDERID'),
            'override_type_name' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_OVERRIDETYPENAME'),
            'retail_partner_name' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_RETAILPARTNERNAME'),
            'arc.order_count' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_ORDERCOUNT'),
            'arc.order_voucher' => JText::_('COM_CN_REPORTS_FORM_LBL_VOUCHER'),
            'arc.order_coupon' => JText::_('COM_CN_REPORTS_FORM_LBL_COUPON'),
            'arc.order_shipping' => JText::_('COM_CN_REPORTS_FORM_LBL_SHIPPING'),
            'arc.order_tax' => JText::_('COM_CN_REPORTS_FORM_LBL_TAX'),
            'order_total' => JText::_('COM_CN_REPORTS_FORM_LBL_OT_TOTAL'),
            'wholesale_price' => JText::_('COM_CN_REPORTS_FORM_LBL_WHOLESALE'),
            'arc.wholesale_markup_amount' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_WHOLESALEMARKUPAMOUNT'),
            'arc.profit_margin_actual' => JText::_('COM_CN_REPORTS_FORM_LBL_APM'),
            'arc.commission_rate' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_COMMISSIONRATE'),
            'arc.commission_amount' => JText::_('COM_CN_REPORTS_FORM_LBL_COMMISSION'),
            'arc.date_start' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_DATESTART'),
            'arc.date_end' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_DATEEND'),
            'created_by_name' => JText::_('COM_CN_REPORTS_ARCHIVECOMMISSIONSALES_COLUMNS_CREATEDBYNAME')
            );
    }

}