Can you pleas help me with this code.... 

```
<?php
    require('fpdf/fpdf.php');

    class PDF_reciept extends FPDF
    {
        function __construct($orientation = 'P', $unit = 'pt', $format = 'Letter', $margin = 40)
        {
            $this->FPDF($orientation, $unit, $format);
            $this->SetTopMargin($margin);
            $this->SetLeftMargin($margin);
            $this->SetRightMargin($margin);
            $this->SetAutoPageBreak(true, $margin);
        }

        function Header()
        {
            $this->SetFont('Arial', 'B', 20);
            $this->SetFillColor(36, 96, 84);
            $this->SetTextColor(225);
            $this->Cell(0, 30, "Nettuts+ Online Store", 0, 1, 'C', true);
        }

        function Footer()
        {
            $this->SetFont('Arial', '', 12);
            $this->SetTextColor(0);
            $this->XY(40, -60);
            $this->Cell(0, 20, "Thank you for shopping at Nettuts+", 'T', 0, 'C');
        }
    }

    $pdf = new PDF_reciept();

    $pdf->Output();
?>

```