void standard_asset() {
set_expiration( db, trx );
const auto& bitusd = create_bitasset("USDBIT", _feedproducer);
_swan = bitusd.id;
_back = asset_id_type();
update_feed_producers(swan(), {_feedproducer});
}
void update_feed_producers(asset_id_type mia, flat_set<account_id_type> producers)
{ update_feed_producers(mia(db), producers); }