protected function _cleanFilter($aFilter)
    {
        $aCleanFilter = false;
        if (is_array($aFilter) && count($aFilter)) {
            foreach ($aFilter as $iKey => $sFilter) {
                if ($sFilter) {
                    $aCleanFilter[$iKey] = $sFilter;
                }
            }
        }

        return $aCleanFilter;
    }