code: def test_contains(self):
      G = self.G()
      G.add_node("A")
      assert "A" in G
      assert [] not in G  # never raise a Key or TypeError in this test
      assert {1: 1} not in G
  
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 6 for calling the HistoricalTests obj's underlying member method code with example usage: obj.test_contains() without return types