Undefined type 'Omnipay\Omnipay'

[CSharpDaddy]

Does anyone know what's causing this?

Im using laravel 9

<?php

namespace App\Http\Controllers;
use Omnipay\Omnipay;

class PaymentController extends Controller
{
    private $gateway;

    public function __construct()
    {
        $this->gateway = Omnipay::create('PayPal_Rest');
    }
}