code: func (n *NamedStmt) MustExec(arg interface{}) sql.Result {
  	res, err := n.Exec(arg)
  	if err != nil {
  		panic(err)
  	}
  	return res
  }
docs: // MustExec execs a NamedStmt, panicing on error
  // Any named placeholder parameters are replaced with fields from arg.