code: def testKCores(self):
      g = Graph(
          11,
          [
              (0, 1),
              (0, 2),
              (0, 3),
              (1, 2),
              (1, 3),
              (2, 3),
              (2, 4),
              (2, 5),
              (3, 6),
              (3, 7),
              (1, 7),
              (7, 8),
              (1, 9),
              (1, 10),
              (9, 10),
          ],
      )
      self.assertTrue(g.coreness() == [3, 3, 3, 3, 1, 1, 1, 2, 1, 2, 2])
      self.assertTrue(g.shell_index() == g.coreness())
  
      edgelist = g.k_core(3).get_edgelist()
      edgelist.sort()
      self.assertTrue(
          edgelist == [(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)]
      )
  
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 3 for calling the DecompositionTests obj's underlying member method code with example usage: obj.testKCores() without return types