@classmethod
    def many_init(cls, *args, **kwargs):
        list_kwargs = {'child_relation': cls(*args, **kwargs)}
        for key in kwargs.keys():
            if key in MANY_RELATION_KWARGS:
                list_kwargs[key] = kwargs[key]
        return IdManyRelatedField(**list_kwargs)
Method from rest_framework.relations.RelatedField That uses our
dataset/ETHPy150Open OpenSlides/OpenSlides/openslides/utils/rest_api.py/IdPrimaryKeyRelatedField.many_init