code: def test_k5(self):
      G = nx.complete_graph(5)
      assert list(nx.triangles(G).values()) == [6, 6, 6, 6, 6]
      assert sum(nx.triangles(G).values()) / 3 == 10
      assert nx.triangles(G, 1) == 6
      G.remove_edge(1, 2)
      assert list(nx.triangles(G).values()) == [5, 3, 3, 5, 5]
      assert nx.triangles(G, 1) == 3
      G.add_edge(3, 3)  # ignore self-edges
      assert list(nx.triangles(G).values()) == [5, 3, 3, 5, 5]
      assert nx.triangles(G, 3) == 5
  
imports: import pytest
  import networkx
label_desc: Use image node_id 4 for calling the TestTriangles obj's underlying member method code with example usage: obj.test_k5() without return types