Prestashop 1.6 自定义模块未显示在前端

我的模块没有显示在前端，我按照这个链接 doc.prestashop.com/display/PS15/Creating+a+PrestaShop+module 在 prestashop 1.6 中创建自定义模块。我已经检查了位置，清除并禁用缓存，卸载并重新安装该模块，但到目前为止没有任何效果。 p.s config.xml 是自动生成的。

这是我的 mymodule.php 代码

<?php
if (!defined('_PS_VERSION_'))
exit;

class MyModule extends Module
{
    public function __construct()
    {
        $this->name= 'mymodule';
        $this->tab = 'front_office_features';
        $this->version = '1.0';
        $this->author = 'Zeeshan Abbas';
        $this->need_instance = 0;
        $this->ps_versions_compliancy = array('min' => '1.5','max' => '1.6');
        $this->dependencies = array('blockcart');

        parent::__construct();



        //it is not 1 it is L ok
        $this->displayName = $this->l('My module');
        $this->description = $this->l('Description of my module');

        $this->confirmUninstall = $this->l('are you sure you want to uninstall?? ');

        if (!Configuration::get('MYMODULE_NAME'))
            $this->warning = $this->l('No name provided');
    }
    public function install() {
        if (Shop::isFeatureActive())
            Shop::setContext(Shop::CONTEXT_ALL);


        return parent::install() &&
            $this->registerHook('leftColumn') &&
            $this->registerHook('header') &&
            Configuration::updateValue('MYMODULE_NAME','my friend');
    }

    public function uninstall()
    {
        if (!parent::uninstall() ||
        !Configuration::deleteByName('MYMODULE_NAME'))
        return false;
      return true;
    }

                /*public function install()
                {
                    if (parent::install() == false)
                    return false;
                    return true;
                }*/



}
?>

这是我的 mymodule.tpl

<!-- Block mymodule -->
<div id="mymodule_block_left" class="block">
<h4>Welcome!</h4>
<div class="block_content">
<p>Hello,
   {if isset($my_module_name) && $my_module_name}
       {$my_module_name}
   {else}
       World
   {/if}
   !       
</p>   
<ul>
  <li><a href="{$my_module_link}" title="Click this link">Click me!</a></li>
</ul>
</div>
</div>
<!-- /Block mymodule -->

The hookDisplayHeader and hookLeftColumn方法缺失。

public function hookDisplayLeftColumn($params)
{
  $this->context->smarty->assign(
      array(
          'my_module_name' => Configuration::get('MYMODULE_NAME'),
          'my_module_link' => $this->context->link->getModuleLink('mymodule', 'display')
      )
  );
  return $this->display(__FILE__, 'mymodule.tpl');
}

public function hookDisplayHeader()
{
  $this->context->controller->addCSS($this->_path.'css/mymodule.css', 'all');
}