def METHOD_NAME(apps, schema_editor):
    NewsletterContent = apps.get_model("newsletters", "NewsletterContent")
    NewsletterEvent = apps.get_model("newsletters", "NewsletterEvent")
    events = NewsletterEvent.objects.all()
    for event in events:
        content = NewsletterContent(
            title_en=event.title_en,
            title_nl=event.title_nl,
            description_en=event.description_en,
            description_nl=event.description_nl,
            newsletter_id=event.newsletter_id
        )
        content.save()
        event.newslettercontent_ptr = content
        event.save()