code: def subtags(subtags):
          
          result = []
  
          if not isinstance(subtags, list):
              subtags = [subtags]
  
          for subtag in subtags:
              for type in tags.types(subtag):
                  result.append(Subtag(subtag, type))
  
          return result
docs: Get a list of existing :class:`language_tags.Subtag.Subtag` objects given the input subtag(s).
  
          :param subtags: string subtag or list of string subtags.
          :return: a list of existing :class:`language_tags.Subtag.Subtag` objects. The return list can be empty.