protected function validateInstallerInstall()
    {
        $field = 'installer';

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

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

        if (empty($value)) {
            $this->setSubmitted('installer', 'default');
            return null;
        }

        $installer = $this->install->getHandler($value);

        if (empty($installer)) {
            $this->setErrorInvalid('installer', $this->translation->text('Installer'));
            return false;
        }

        return true;
    }