code: func Lower(db XODB, v0 string, v1 pgtypes.Anyrange) (pgtypes.Anyelement, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT pg_catalog.lower($1, $2)`
  
  	// run query
  	var ret pgtypes.Anyelement
  	XOLog(sqlstr, v0, v1)
  	err = db.QueryRow(sqlstr, v0, v1).Scan(&ret)
  	if err != nil {
  		return pgtypes.Anyelement{}, err
  	}
  
  	return ret, nil
  }
docs: // Lower calls the stored procedure 'pg_catalog.lower(text, anyrange) anyelement' on db.