code: function CheckTodoInENML(text, index, check){
  
      var todo_cout = 0;
      var writer = new XMLWriter();
      var parser = new SaxParser(function(cb) {
  
        cb.onStartElementNS(function(elem, attrs, prefix, uri, namespaces) {
  
          writer.startElement(elem);
  
  
          if(elem == 'en-todo' && index == todo_cout++){
  
            if(attrs) attrs.forEach(function(attr) {
              if(attr[0] == 'checked') return;
              writer.writeAttribute(attr[0], attr[1]);
            });
  
            if(check)  writer.writeAttribute('checked', 'true');
          }else{
  
            if(attrs) attrs.forEach(function(attr) {
              writer.writeAttribute(attr[0], attr[1]);
            });
          }
        });
        cb.onEndElementNS(function(elem, prefix, uri) {
  
          writer.endElement();
        });
        cb.onCharacters(function(chars) {
          writer.text(chars);
        });
  
      });
  
      parser.parseString(text);
      return writer.toString();
    }
docs: CheckTodoInENML
  Rewrite ENML content by changing check/uncheck value of the TODO in given position.
  
  @param { string } text (ENML)
  @param { int }  index
  @param { bool } check
  @return string - ENML (the new content)