code: def testClusteringSizes(self):
      self.assertTrue(self.cl.sizes() == [3, 4, 1, 0, 2])
      self.assertTrue(self.cl.sizes(2, 4, 1) == [1, 2, 4])
      self.assertTrue(self.cl.size(2) == 1)
  
imports: import math
  import random
  import unittest
  from igraph import Clustering, CohesiveBlocks, Cover, Graph, Histogram, InternalError, UniqueIdGenerator, VertexClustering, compare_communities, split_join_distance, set_random_number_generator
label_desc: Use image node_id 5 for calling the ClusteringTests obj's underlying member method code with example usage: obj.testClusteringSizes() without return types