'For each region in the object:
Deletes all of the (carrier-less) FeedItems in the region.
Batch create all of the FeedItems in order for each region.
-- feed - object of regions that point to a list of feed
element IDs (as well as their type) .
\'us\': [
[\'app\', 36L],
[\'app\', 42L],
[\'collection\', 12L],
[\'brand\', 12L]'

def put(self, request, *args, **kwargs):

    regions = [mkt.regions.REGIONS_DICT[region].id for region in request.data.keys()]
    FeedItem.objects.filter(carrier=None, region__in=regions).delete()
    feed_items = []
    for (region, feed_elements) in request.data.items():
        for (order, feed_element) in enumerate(feed_elements):
            try:
                (item_type, item_id) = feed_element
            except ValueError:
                return response.Response('Expected    two-element    arrays.', status=status.HTTP_400_BAD_REQUEST)
            feed_item = {'region': mkt.regions.REGIONS_DICT[region].id, 'order': order, 'item_type': item_type}
            feed_item[(item_type + '_id')] = item_id
            feed_items.append(FeedItem(**feed_item))
    FeedItem.objects.bulk_create(feed_items)
    feed_item_ids = list(FeedItem.objects.filter(region__in=regions).values_list('id', flat=True))
    FeedItem.get_indexer().index_ids(feed_item_ids, no_delay=True)
    return response.Response(status=status.HTTP_201_CREATED)
