code: def testCoverSizes(self):
      self.assertTrue(self.cl.sizes() == [4, 5, 0, 2])
      self.assertTrue(self.cl.sizes(1, 3, 0) == [5, 2, 4])
      self.assertTrue(self.cl.size(1) == 5)
      self.assertTrue(self.cl.size(2) == 0)
  
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 4 for calling the CoverTests obj's underlying member method code with example usage: obj.testCoverSizes() without return types