protected function _amplifyModifiers($value, $modifiers)
    {
        /** @var $helper Aoe_ExtendedFilter_Helper_Data */
        $helper = Mage::helper('Aoe_ExtendedFilter');
        foreach (explode('|', $modifiers) as $part) {
            if (empty($part)) {
                continue;
            }
            $params = explode(':', $part);
            $modifier = array_shift($params);
            $callback = $helper->getModifier($modifier);

            // Legacy modifiers
            if (!is_callable($callback) && isset($this->_modifiers[$modifier])) {
                $callback = $this->_modifiers[$modifier];
                if (!$callback) {
                    $callback = $modifier;
                }
            }

            if (is_callable($callback)) {
                array_unshift($params, $value);
                $value = call_user_func_array($callback, $params);
            }
        }

        return $value;
    }