code: func GetMulticastGroupsForDevEUI(db sqlx.Queryer, devEUI lorawan.EUI64) ([]uuid.UUID, error) {
  	var out []uuid.UUID
  
  	err := sqlx.Select(db, &out, `
  		select
  			multicast_group_id
  		from
  			device_multicast_group
  		where
  			dev_eui = $1`,
  		devEUI[:])
  	if err != nil {
  		return nil, handlePSQLError(err, "select error")
  	}
  
  	return out, nil
  }
docs: // GetMulticastGroupsForDevEUI returns the multicast-group ids to which the
  // given Device EUI belongs.