Vanilla\Addon::canonicalizeLocale PHP Method

    private static function canonicalizeLocale($locale)
    {
        $locale = str_replace(array('-', '@'), array('_', '__'), $locale);
        $parts = explode('_', $locale, 2);
        if (isset($parts[1])) {
            $parts[1] = strtoupper($parts[1]);
        }
        $result = implode('_', $parts);
        // Remove everything from the string except letters, numbers, dashes, and underscores.
        $result = preg_replace('/([^\\w-])/', '', $result);
        // This is a bit of a kludge, but we are deprecating en_CA in favour of just en.
        if ($result === 'en_CA') {
            $result = 'en';
        }
        return $result;
    }