class_docstr: Unit tests for the approximate minimum weighted vertex cover
  function,
  :func:`~networkx.algorithms.approximation.vertex_cover.min_weighted_vertex_cover`.
code: def test_unweighted_self_loop(self):
      slg = nx.Graph()
      slg.add_node(0)
      slg.add_node(1)
      slg.add_node(2)
  
      slg.add_edge(0, 1)
      slg.add_edge(2, 2)
  
      cover = min_weighted_vertex_cover(slg)
      assert 2 == len(cover)
      assert is_cover(slg, cover)
  
file_path: networkx/networkx/algorithms/approximation/tests/test_vertex_cover.py
imports: import networkx
  from networkx.algorithms.approximation import min_weighted_vertex_cover
label_desc: Use image node_id 4 for calling the TestMWVC obj's underlying member method code with example usage: obj.test_unweighted_self_loop() without return types