docstr: Should be able to return the subgraph with the specified node
docstr_tok: ["Should","be","able","to","return","the","subgraph","with","the","specified","node"]
code: def test_isolates_nodes_and_edges(self):
      """Should be able to return the subgraph with the specified node"""
  
      edges = [(0, 1), (1, 2), (1, 3), (5, 6), (4, 5)]
      isolated_nodes = [7, 8, 9]
      sm = StructureModel()
      sm.add_edges_from(edges)
      sm.add_nodes_from(isolated_nodes)
      subgraph = sm.get_markov_blanket(5)
      expected_edges = [(5, 6), (4, 5)]
      expected_graph = StructureModel()
      expected_graph.add_edges_from(expected_edges)
  
      assert set(subgraph.nodes) == set(expected_graph.nodes)
      assert set(subgraph.edges) == set(expected_graph.edges)
  
imports: import pytest
  from networkx.exception import NodeNotFound
  from causalnex.structure import StructureModel
label_desc: Use image node_id 6 for calling the TestStructureModelGetMarkovBlanket obj's underlying member method code with example usage: obj.test_isolates_nodes_and_edges() without return types