pretty.py

# Version 1

    return Response(dict([(
        int(pk),
        {'lowest_stock': ItemModel.objects.get(id=int(pk)) \
            .get_lowest_stock_for_subbooking(subbooking)}
    ) for pk in request.QUERY_PARAMS.get('item_models', '').split(',')]))

# Version 2

    result = dict()
    pks = [int(pk) for pk in request.QUERY_PARAMS.get('item_models', '').split(',')]
    models = ItemModel.objects.filter(id__in=pks)
    for m in models:
        result[m.pk] = {'lowest_stock': m.get_lowest_stock_for_subbooking(subbooking)}
    return Response(result)

# Version 3

    pks = [int(pk) for pk in request.QUERY_PARAMS.get('item_models', '').split(',')]
    models = ItemModel.objects.filter(id__in=pks)
    result = {m.pk: {'lowest_stock': m.get_lowest_stock_for_subbooking(subbooking)} for m in models}
    return Response(result)