public function withholdingCertificate($invoice_uuid)
    {
        $provider = auth()->user()->provider;
        $invoice = Payment::where('uuid', $invoice_uuid)
            ->where('provider_id', $provider->id)
            ->with('client')
            ->firstOrFail();

        $pdf = \PDF::loadView('provider.invoices.withholding-certificate', compact('invoice', 'provider'));
        
        return $pdf->download('certificat-retenue-' . $invoice->invoice_number . '.pdf');
    }