code: def test_empty_subgraph(self):
      # Subgraph of an empty graph is an empty graph. test 1
      nullgraph = nx.null_graph()
      E5 = nx.empty_graph(5)
      E10 = nx.empty_graph(10)
      H = E10.subgraph([])
      assert nx.is_isomorphic(H, nullgraph)
      H = E10.subgraph([1, 2, 3, 4, 5])
      assert nx.is_isomorphic(H, E5)
  
imports: import pytest
  import networkx
  from networkx import convert_node_labels_to_integers
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 32 for calling the HistoricalTests obj's underlying member method code with example usage: obj.test_empty_subgraph() without return types