public function write($sessionId, $sessionData){
        //si la sesión está abierta y tengo lock 
        if($this->opened){
            $sql= $this->connection->connection->prepare('REPLACE INTO sessions (session_id, session_data, session_expiration) VALUES(:id, :data, :expiration)');
            $sql->bindValue('id', $sessionId);
            $sql->bindValue('data', $sessionData);
            $fecha= new \DateTime();
            $fecha->add(new \DateInterval($this->expirationTime));
            $sql->bindValue('expiration', $fecha->format('Y-m-d H:i:s'));
            return $sql->execute() === TRUE;
        }
        else{
            return FALSE;
        }
    }