How to convert hex string to string or ubytes? Thanks.

[FrankLike]

On Monday, 5 February 2018 at 06:12:22 UTC, H. S. Teoh wrote:
> On Mon, Feb 05, 2018 at 05:48:00AM +0000, FrankLike via

> 	assert(str == "Hello world!");

Thanks.very good!