parse static method
Implementation
static HackerNewsItemUrl? parse(String url) {
var matches = RegExp(r'(?:https?:)?\/\/news\.ycombinator\.com\/item\?id=(?<item>[0-9]+)').allMatches(url);
var _id = matches.getValue("item");
if (_id == null) return null;
return HackerNewsItemUrl._(_id);
}