docs: def similar(self):
          """
          iterator over similar artists as :class:`Artist` objects
          """
          if self._similar is None:
              self._similar = [
                  Artist(artist['ArtistID'], artist['Name'], self._connection)
                  for artist in self._connection.request(
                      'artistGetSimilarArtists',
                      {'artistID': self.id},
                      self._connection.header('artistGetSimilarArtists'))[1]['SimilarArtists']]
          return iter(self._similar)