public HashMap<Tag, String> retrieveTags(String fileName){
        HashMap<Tag,String> tag = new HashMap<>();
        //<track number> - <title>
        String[] dividers = pattern.split("<[^>]*>");
        
        List<String> usedTags = new ArrayList<>();
        for (Tag t : Tag.values()){
            if (pattern.contains(t.getPattern())) {
                usedTags.add(t.getPattern());
            }
        }
        
        return tag;
    }