public static function sign_up($username, $password, $role, $email, $country)
 {
     DAL::addUser(Cleaning::cleanString($username), Cleaning::cleanString($password), Cleaning::cleanEmail($email), $role, 0, $country);
     Model_user::sign_in($username, $password);
 }
 private function sign_in()
 {
     global $rep, $views, $TmessagesConnection;
     if (isset($_POST['sign_in'])) {
         // If we clicked on the sign_in button
         $username = isset($_POST['username']) ? $_POST['username'] : '';
         $pwd = isset($_POST['password']) ? $_POST['password'] : '';
         if (Validation::val_username($username, $TmessagesConnection) && Validation::val_password($pwd, $TmessagesConnection)) {
             //variable verifications
             Model_user::sign_in($username, $pwd);
             //connect the user
             //maybe update messagesError to explain the user the problem ?
         }
     }
     $cont = new Controller_visitor("home");
     // if variables are not correct
 }