goxpath.go
func (xp XPathExec) MustExec(t tree.Node, opts ...FuncOpts) tree.Result {
	res, err := xp.Exec(t, opts...)
	if err != nil {
		panic(err)
	}
	return res
}
func (xp XPathExec) MustExec(t tree.Node, opts ...FuncOpts) tree.Result {
	res, err := xp.Exec(t, opts...)
	if err != nil {
		panic(err)
	}
	return res
}
//MustExec is like Exec, but panics instead of returning an error.