How do I call a model via the artisan command in Laravel 5?

For background, I'm a laravel 5 newbie, but I've used laravel 4 in my past projects.

In laravel 4 I just call the model directly in the artisan command, but now how can I name the model inside the artisan command. here's my current code:

<?php 
   namespace App\Console\Commands;
   use Illuminate\Console\Command;
   use App\Models\sampleModel as sampleModel;

   class testCommand extends Command {

  /**
  * The console command name.
  *
  * @var string
  */
   protected $name = 'test';

  /**
  * The console command description.
  *
  * @var string
  */
   protected $description = 'Command description.';

   /**
   * Create a new command instance.
   *
   * @return void
   */
    public function __construct()
    {
        parent::__construct();
    }

   /**
   * Execute the console command.
   *
   * @return mixed
   */
    public function fire()
    {
        sampleModel::sampleMethod();
    }

}