code: def _has_converged(centroids, old_centroids):
      
      return (set([tuple(a) for a in centroids]) == set([tuple(a) for a in old_centroids]))
docs: Stop if centroids stop to update
      Parameters
      -----------
      centroids: array-like, shape=(K, n_samples)     
      old_centroids: array-like, shape=(K, n_samples)
      ------------    
      returns
      True: bool