WooCommerce Germanized Pro 2.6.1 - clone packing slip page on PDF

functions.php

/*
 * WooCommerce Germanized Pro 2.1.6
 * Function to clone packing slip on PDF
 **/
function my_clone_packing_slip( $attachment, $document ) {

	if ( $document->type === 'packing_slip' ) {

			WC_germanized_pro()->set_upload_dir_filter();
			$path = get_attached_file( $attachment );
			WC_germanized_pro()->unset_upload_dir_filter();
			
			if ( ! class_exists( 'Fpdi' ) ) {
				require_once( 'fpdi/fpdi.php' ); // include FPDI library in your folder
			}
			
			if ( class_exists('TCPDF') && class_exists('Fpdi') ) { // TCPDF should be included by Germanized Pro
				
				// initiate FPDI
				$pdf = new Fpdi();

				$pageCount = $pdf->setSourceFile($path);
				$tplIdx = $pdf->importPage(1, '/MediaBox');
				
				// remove default header/footer
				$pdf->setPrintHeader( false );
				$pdf->setPrintFooter( false );

				$pdf->addPage();
				$pdf->useTemplate( $tplIdx, 0, 0 );
				
				$pdf->addPage();
				$pdf->useTemplate( $tplIdx, 0, 0 );
						
				$pdf->Output( $path, 'F' );
				
			}		
	}
	
}
add_action( 'woocommerce_gzdp_pdf_attachment_updated', 'my_clone_packing_slip', 10, 2 );