def METHOD_NAME(self, sibling_count) -> List[Project]:
    siblings = ProjectFactory.create_batch(sibling_count, title=factory.Sequence(lambda n: 'child%d' % n))
    sibling_rp = []
    # iterate i, i+1
    for left, right in zip(siblings, siblings[1:]):
        sibling_rp.append(
            RelatedProject.objects.create(
                project=left,
                related_project=right,
                relation=RelatedProject.PROJECT_RELATION_SIBLING
            )
        )
    return siblings