docstr: Should be able to return the largest subgraph
docstr_tok: ["Should","be","able","to","return","the","largest","subgraph"]
code: def test_get_largest_subgraph(self, test_input, expected):
      """Should be able to return the largest subgraph"""
  
      sm = StructureModel()
      sm.add_edges_from(test_input)
      largest_subgraph = sm.get_largest_subgraph()
  
      expected_graph = StructureModel()
      expected_graph.add_edges_from(expected)
  
      assert set(largest_subgraph.nodes) == set(expected_graph.nodes)
      assert set(largest_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 1 for calling the TestStructureModelGetLargestSubgraph obj's underlying member method code with example usage: obj.test_get_largest_subgraph(test_input, expected) without return types