Souke/backend/forms/ReportPaymentsForm.php

<?php

namespace backend\forms;

use yii\base\Model;

/**
 * UploadForm is the model behind the upload form.
 */
class ReportPaymentsForm extends Model
{
    var $date_start;
    var $date_end;

    /**
     * @return array the validation rules.
     */
    public function rules()
    {
        return [
            [['date_start', 'date_end'], 'required'],
            [['date_start', 'date_end'], 'safe'],
        ];
    }

    public function attributeLabels()
    {
        return [
            'date_start' => "Date de début",
            'date_end' => "Date de fin"
        ];
    }
}

?>