/**
  * used to set self::$productsPerPageOptions, set $includeAllProductsOption true if
  * 'All' should be included 
  * 
  * @param array $productsPerPageOptions   array with all options
  *                                          array(
  *                                              '5'  => '5',
  *                                              '10' => '10',
  *                                              ...
  *                                          )
  * @param bool  $includeAllProductsOption set if 'All' should be included
  * 
  * @return void
  */
 public static function setProductsPerPageOptions(array $productsPerPageOptions, $includeAllProductsOption = false)
 {
     if (is_array($productsPerPageOptions)) {
         self::$productsPerPageOptions = $productsPerPageOptions;
         if ($includeAllProductsOption) {
             self::$productsPerPageOptions['0'] = _t('SilvercartConfig.PRODUCTSPERPAGE_ALL');
         }
     }
 }