Laravel\Cashier\Cashier::guessCurrencySymbol PHP Method

    protected static function guessCurrencySymbol($currency)
    {
        switch (strtolower($currency)) {
            case 'usd':
            case 'aud':
            case 'cad':
                return '$';
            case 'eur':
                return '€';
            case 'gbp':
                return '£';
            default:
                throw new Exception("Unable to guess symbol for currency. Please explicitly specify it.");
        }
    }