undefined variable $activeTab in listPage Class

I am getting a error undefined variable $activeTab on the list page

<?php

namespace App\Filament\Resources\BookingResource\Pages;

use App\Filament\Resources\BookingResource;
use Filament\Actions\CreateAction;
use Filament\Resources\Pages\ListRecords;
use Filament\Resources\Pages\ListRecords\Tab;
use Illuminate\Database\Eloquent\Builder;

class ListBookings extends ListRecords
{
    //public ?string $activeTab = 'active';
    protected static string $resource = BookingResource::class;

    public function getTabs(): array
    {
        return [
            'all' => Tab::make(),
            'active' => Tab::make(),
            'inactive' => Tab::make(),
        ];
    }

    public function getDefaultActiveTab(): string | int | null
    {
        return 'active';
    }

    protected function getHeaderActions(): array
    {
        return [
            CreateAction::make()->slideOver(),
        ];
    }
}

<?php

namespace App\Filament\Resources\BookingResource\Pages;

use App\Filament\Resources\BookingResource;
use Filament\Actions\CreateAction;
use Filament\Resources\Pages\ListRecords;
use Filament\Resources\Pages\ListRecords\Tab;
use Illuminate\Database\Eloquent\Builder;

class ListBookings extends ListRecords
{
    //public ?string $activeTab = 'active';
    protected static string $resource = BookingResource::class;

    public function getTabs(): array
    {
        return [
            'all' => Tab::make(),
            'active' => Tab::make(),
            'inactive' => Tab::make(),
        ];
    }

    public function getDefaultActiveTab(): string | int | null
    {
        return 'active';
    }

    protected function getHeaderActions(): array
    {
        return [
            CreateAction::make()->slideOver(),
        ];
    }
}