days-back – integer – the number of days to look back for posts. Optional. no-item-action – string – what action to take when no items are found in the feed. Valid values: postpone-campaign(postpones the campaign till next day). Optional. send-only-unique-items – string – if we should only send unique items. if no items are found, then no-item-action is applied. Valid values: (yes or no). Optional.