how load helper in a model?

thanks!

finally, I load the helper in controller:

in model:
protected $validationRules = [
'nom' => ['rules' => 'required|min_length[2]|max_length[100]'],
'nom_anterior' => ['rules' => 'min_length[2]|max_length[100]'],
'imo' => ['rules' => 'required|exact_length[10]'],
];

in controller:
$validation = \Config\Services::validation();

$iotsModel = new IotsModel();
$rules = $iotsModel->getValidationRules();

$idioma = comprovacio_idioma_usuari();

$rules1 = [];
foreach($rules as $key => $rule)
{
$rule['label'] = lang('Admin.'.$key, [], $idioma);
array_push($rules1, $rule);
}

$validation->setRules($rules1);

surely there are more elegant ways, but it works perfectly!