laravel_sketch/app/Providers/AppServiceProvider.php

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Validation\Validator;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        if ($this->app->environment('local')) {
            $this->app->register(\Laravel\Telescope\TelescopeServiceProvider::class);
            $this->app->register(TelescopeServiceProvider::class);
        }
    }

    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        //
    }
}