code: def test_null_graph(self):
      G = nx.DiGraph()
      assert list(nx.strongly_connected_components(G)) == []
      assert list(nx.kosaraju_strongly_connected_components(G)) == []
      with pytest.deprecated_call():
          assert (
              list(nx.strongly_connected_components_recursive(G)) == []
          )
      assert len(nx.condensation(G)) == 0
      pytest.raises(
          nx.NetworkXPointlessConcept,
          nx.is_strongly_connected,
          nx.DiGraph(),
      )
  
file_path: networkx/networkx/algorithms/components/tests/test_strongly_connected.py
imports: import pytest
  import networkx
  from networkx import NetworkXNotImplemented
label_desc: Use image node_id 11 for calling the TestStronglyConnected obj's underlying member method code with example usage: obj.test_null_graph() without return types