private RobotsFile FromTokens(IEnumerable <Token> tokens, Uri baseUri)
        {
            var validationResult = PatternValidator.Validate(tokens);

            if (validationResult.IsValid)
            {
                return(new RobotsFile(baseUri)
                {
                    SiteAccessEntries = TokenParser.GetSiteAccessEntries(tokens),
                    SitemapEntries = TokenParser.GetSitemapUrlEntries(tokens)
                });
            }

            return(RobotsFile.AllowAllRobots(baseUri));
        }