Fatal error: Uncaught exception Error with message Function name must be a string thrown in system/modules/core/library/Contao/Controller.php on line 2289

#0 system/modules/core/library/Contao/DcaExtractor.php(291): Contao\Controller->loadDataContainer('tl_page')
#1 system/modules/core/library/Contao/DcaExtractor.php(114): Contao\DcaExtractor->createExtract()
#2 system/modules/core/library/Contao/Model/QueryBuilder.php(38): Contao\DcaExtractor->__construct('tl_page')
#3 system/modules/core/library/Contao/Model.php(595): Contao\Model\QueryBuilder::find(Array)
#4 system/modules/core/library/Contao/Model.php(517): Contao\Model::find(Array)
#5 system/modules/core/models/PageModel.php(330): Contao\Model::findBy(Array, Array, Array)
#6 index.php(82): Contao\PageModel::findPublishedByIdOrAlias('buch')
#7 index.php(407): Index->run()
#8 {main}