Laravel default Exception Handler

Handler.php

<?php
namespace App\Exceptions;

class Handler extends \Laravel\Lumen\Exceptions\Handler
{
    public function render($request, Throwable $exception)
    {
        if ($exception instanceof CustomException) {
            return response()->json(['error' => 'Oops!'], 400);
        }
        return parent::render($request, $exception);
    }
}