'apprenticeship_document' => array(
      'exclude' => 1,
      'label' => 'LLL:EXT:stellen/Resources/Private/Language/locallang_db.xlf:tx_stellen_domain_model_institution.apprenticeship_document',
      'config' => TYPO3CMSCoreUtilityExtensionManagementUtility::getFileFieldTCAConfig(
        'apprenticeshipDocument',
        array('maxitems' => 1),
        '*'
      ),
    ),

/**
 * apprenticeshipDocument
 *
 * @var TYPO3CMSExtbaseDomainModelFileReference
 */
protected $apprenticeshipDocument = NULL;

/**
 * Returns the apprenticeshipDocument
 *
 * @return TYPO3CMSExtbaseDomainModelFileReference $apprenticeshipDocument
 */
public function getApprenticeshipDocument() {
    return $this->apprenticeshipDocument;
}

/**
 * Sets the apprenticeshipDocument
 *
 * @param TYPO3CMSExtbaseDomainModelFileReference $apprenticeshipDocument
 * @return void
 */

public function setApprenticeshipDocument(TYPO3CMSExtbaseDomainModelFileReference $apprenticeshipDocument) {
    $this->apprenticeshipDocument = $apprenticeshipDocument;
}