code: def test_add_remove_node(self):
      G = self.G()
      G.add_node("A")
      assert G.has_node("A")
      G.remove_node("A")
      assert not G.has_node("A")
  
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 3 for calling the HistoricalTests obj's underlying member method code with example usage: obj.test_add_remove_node() without return types