code: def testSubgraph(self):
      g = Graph.Lattice([10, 10], circular=False, mutual=False)
      g.vs["id"] = list(range(g.vcount()))
  
      vs = [0, 1, 2, 10, 11, 12, 20, 21, 22]
      sg = g.subgraph(vs)
  
      self.assertTrue(
          sg.isomorphic(
              Graph.Lattice([3, 3], circular=False, mutual=False)
          )
      )
      self.assertTrue(sg.vs["id"] == vs)
  
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 1 for calling the SubgraphTests obj's underlying member method code with example usage: obj.testSubgraph() without return types