code: def test_cubical(self):
      G = nx.cubical_graph()
      assert list(nx.triangles(G).values()) == [0, 0, 0, 0, 0, 0, 0, 0]
      assert nx.triangles(G, 1) == 0
      assert list(nx.triangles(G, [1, 2]).values()) == [0, 0]
      assert nx.triangles(G, 1) == 0
      assert nx.triangles(G, [1, 2]) == {1: 0, 2: 0}
  
imports: import pytest
  import networkx
label_desc: Use image node_id 3 for calling the TestTriangles obj's underlying member method code with example usage: obj.test_cubical() without return types