Not working in Laravel 5.4

[PSuresh3one]

I'm using fpdf and fpdi in my laravel project, I want to skip pages from my original pdf and output modified pdf, but is showing the following error

Here is my code:

require_once('fpdf.php');
require_once "fpdi.php";
$pdf = new FPDI(); //FPDI extends TCPDF
$pageCount = $pdf->setSourceFile('Seeking-Civility.pdf');

// Array of pages to skip -- modify this to fit your needs
$skipPages = [21,22,23,24,25,26,27,28,29];

// Add all pages of source to new document
for( $pageNo=1; $pageNo<=$pageCount; $pageNo++ )
{
// Skip undesired pages
if( in_array($pageNo,$skipPages) )
continue;

//  Add page to the document
$templateID = $pdf->importPage($pageNo);
$pdf->getTemplateSize($templateID);
$pdf->addPage();
$pdf->useTemplate($templateID);

}

$pdf->Output();

[JanSlabon]

I guess you're in a namespaced controller class. So simply use new \FPDI().
Additionally I would suggest to load the classes via composer.
As this is not a bug or issue in FPDI I will close this issue directly. Feel free to use Stackoverflow for further questions/problems.