Ojs\CoreBundle\Service\SampleObjectLoader::loadJournalTheme PHP Method

    public function loadJournalTheme()
    {
        $journal = $this->em->getRepository(Journal::class)->find(1);
        $entity = new JournalTheme();
        $entity->setTitle('Sample Journal Theme')->setJournal($journal)->setPublic(true);
        $this->em->persist($entity);
        $this->em->flush();
        return $entity->getId();
    }