/**
* Replaces troublesome characters with underscores and prefixes if necessary
*
* @param string $id of cache to sanitize
* @return string
*/
protected function _sanitize_id($id)
{
static $prefix = null;
if (is_null($prefix)) {
$prefix = Arr::get($this->_config, 'prefix', '');
}
return parent::_sanitize_id($prefix . $id);
}
