Mp3TagLib.Tager.GetIncorectTags C# (CSharp) Method

        public IEnumerable<Tags> GetIncorectTags(Mask mask)
        {
            var tags = _currentFile.GetTags();
            return (from tag in tags.TagsDictionary where string.IsNullOrEmpty(tag.Value) && mask.Contains(tag.Key.ToString().ToLower()) select tag.Key).ToList();
        }

        string GetFileInfo(Mask mask)
        {
            var           badTags = _tager.GetIncorectTags(mask);
            StringBuilder builder = new StringBuilder();

            foreach (var badTag in badTags)
            {
                builder.Append(badTag + " is empty;");
            }

            if (badTags.Any())
            {
                return("Bad tags:" + builder);
            }

            return("Bad name");
        }