ef METHOD_NAME(self):
  "Test if there is an item in the cluster that has a different cardinality"
  data = [ (1,5), (2,5), (2,6), (3,4), (3,5), (3,6,7), (7,3), (8,1), (8,2), (8), (9,2), (9,3) ]
  self.assertRaises(ValueError, KMeansClustering, data)