public function setCustomer(CNabuCustomer $nb_customer, $field = NABU_CUSTOMER_FIELD_ID)
    {
        $this->nb_customer = $nb_customer;
        if ($this instanceof CNabuDataObject) {
            if ($nb_customer !== null) {
                $this->transferValue($nb_customer, NABU_CUSTOMER_FIELD_ID, $field);
            } else {
                $this->setValue(NABU_CUSTOMER_FIELD_ID, null);
            }
        }

        return $this;
    }