protected function normalizeKey($key)
    {
        if (preg_match(static::$arrayKey, $key, $matches)) {
            $key = $matches[1];
            return $key;
        }
        return $key;
    }
protected function normalizeKey($key)
    {
        if (preg_match(static::$arrayKey, $key, $matches)) {
            $key = $matches[1];
            return $key;
        }
        return $key;
    }
protected function normalizeKey ( $ key ) { if ( preg_match ( static :: $ arrayKey , $ key , $ matches ) ) { $ key = $ matches [ 1 ] ; return $ key ; } return $ key ; }
Return a key that can be used on the current subject.

@param $key
@param $matches
@return mixed
Return a key that can be used on the current subject .