parse static method
Implementation
static YoutubeUserUrl? parse(String url) {
var matches = RegExp(
r'(?:https?:)?\/\/(?:[A-z]+\.)?youtube.com\/user\/(?<username>[A-z0-9]+)\/?')
.allMatches(url);
var username = matches.getValue("username");
if (username == null) return null;
return YoutubeUserUrl._(username);
}