Database::getOne PHP Method

    public function getOne($sql)
    {
        $res = $this->doQuery($sql);
        if ($res && $this->getNumRows($res)) {
            $row = mysqli_fetch_array($res);
            return $row ? reset($row) : false;
        }
        return false;
    }

 public function userAlreadyVote($user)
 {
     if (is_object($user) && isset($user->id)) {
         $userId = $user->id;
     } else {
         if (is_numeric($user)) {
             $userId = $user;
         } else {
             return null;
         }
     }
     if (Database::getOne('votes', array('possibility' => $this->id, 'user' => $userId))) {
         return true;
     } else {
         return false;
     }
 }