protected function validateMajorUnitCurrency()
    {
        $field = 'major_unit';

        if ($this->isExcluded($field)) {
            return null;
        }

        $value = $this->getSubmitted($field);

        if ($this->isUpdating() && !isset($value)) {
            $this->unsetSubmitted($field);
            return null;
        }

        if (empty($value) || mb_strlen($value) > 50) {
            $this->setErrorLengthRange($field, $this->translation->text('Major unit'), 1, 50);
            return false;
        }

        return true;
    }