a "user can register" use case

Register.php

<?php

namespace Ushahidi\Usecase\User;

use Ushahidi\Entity\User;
use Ushahidi\Entity\UserRepository;
use Ushahidi\Tool\Validator;

class Register
{
	private $repo;
	private $valid;

	public function __construct(UserRepository $repo, Validator $valid)
	{
		$this->repo = $repo;
		$this->valid = $valid;
	}

	public function interact(User $user)
	{
		$this->valid->check($user);
		$this->repo->add($user);
		return $user->id;
	}
}