code: func Polygon(db XODB, v0 pgtypes.Path, v1 pgtypes.Box, v2 pgtypes.Circle, v3 int, v4 pgtypes.Circle) (pgtypes.Polygon, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT pg_catalog.polygon($1, $2, $3, $4, $5)`
  
  	// run query
  	var ret pgtypes.Polygon
  	XOLog(sqlstr, v0, v1, v2, v3, v4)
  	err = db.QueryRow(sqlstr, v0, v1, v2, v3, v4).Scan(&ret)
  	if err != nil {
  		return pgtypes.Polygon{}, err
  	}
  
  	return ret, nil
  }
docs: // Polygon calls the stored procedure 'pg_catalog.polygon(path, box, circle, integer, circle) polygon' on db.