How to create a provider of validation

Hello,
I try to create my own validation, But I have an error of provider because I do not know what to put.

//vendor/maitrepylos/Validation.php

<?php

namespace Maitrepylos;


use Cake\Datasource\ConnectionManager;

class Validation extends \Cake\Validation\Validation {


    public static function uniqueIdentifiant($check){

        $pdo = ConnectionManager::get('default');
        $sql =  'SELECT count(*) as compteur FROM catalogue WHERE t_identifiant = ?';
        $r = $pdo->prepare($sql);
        $r->execute([$check]);
        $d = $r->fetch(\PDO::FETCH_OBJ);

        if($d->compteur > 0){
            return false;
        }

        return true;



    }

}

//App/Model/Validation/ProjectValidation.php

<?php
namespace App\Model\Validation;


use Cake\Datasource\ConnectionManager;
use Cake\Validation\Validator;

class ProjectValidation
{
    public $validator = null;
    public function __construct()
    {
        $this->validator = new Validator();


    }

    public function newFiche(){

        $this->validator->requirePresence('t_titre', true)
            ->notEmpty('t_titre', 'Le nom de la fiche ne peut être absente')
            ->notEmpty('d_date_creation','La date ne peut être vide')
            ->add('d_date_creation',[
                'checkDate'=>[
                    'rule'=>['date','dmy'],
                    'message' => 'La date doit-être au format d/m/Y'
                ]
            ])
            ->notEmpty('t_identifiant', 'L\'identifiant ne peut être vide')
            ->add('t_identifiant',[
                'single' =>
                    [
                        'rule' => ['uniqueIdentifiant'],
                        'provider'=>'??????????????????????????', //I don't know 
                       'message' => 'test unique'
                    ]

            ]);

        return $this->validator;

    }


}

Thank you for your help

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