public function cetak($id){
        try {
            $dt = Purchase_order::with('suppliers')->find($id);

            $pdf = PDF::loadview('admin.po.pdf',compact('dt'))->setPaper('a4', 'landscape');
            return $pdf->stream();

        } catch (\Exception $e) {
            \Session::flash('gagal',$e->getMessage().' ! '.$e->getLine());
        }

        return redirect()->back();
    }