code: def handle_ref(attr, language=DEFAULT_LANG):
          
          ref = attr.get('$ref', None)
          if ref is None:
              raise NotFoundException('No $ref in attribute')
  
          _, files, _type, _id = ref.split('/')
  
          if 'files' != files:
              raise NotFoundException('Mandatory "files" path was not found in $ref')
  
          if _type not in ('fix', 'description'):
              raise NotFoundException('Mandatory fix or description not found in $ref')
  
          if not _id.isdigit():
              raise NotFoundException('Mandatory integer ID not found in $ref')
  
          file_path = os.path.join(DBVuln.get_json_path(language=language),
                                   _type,
                                   '%s.md' % _id)
  
          if not os.path.exists(file_path):
              raise NotFoundException('$ref points to a non existing file')
  
          return file(file_path).read()
docs: Receives something like:
  
             {
               "$ref": "#/files/description/1"
             },
  
          Or:
  
             {
               "$ref": "#/files/fix/39"
             }
  
          And returns the contents of the description or fix file.
  
          :param attr: A dict containing a reference
          :param language: The user's language (en, es, etc.)
          :return: Markdown referenced by the attr