code: def tag(self, *tag, **kwtags):
          
          if not tag:
              pass
          elif len(tag) == 1 and isinstance(tag[0], dict):
              self._meta.update(tag[0])
          else:
              raise TypeError('Tags must be provided as key-word arguments or '
                              'a dictionary')
          self._meta.update(kwtags)
          return self
docs: Tag a Property instance with metadata dictionary