code: def test_freeze(self):
      G = nx.freeze(self.G)
      assert G.frozen
      pytest.raises(nx.NetworkXError, G.add_node, 1)
      pytest.raises(nx.NetworkXError, G.add_nodes_from, [1])
      pytest.raises(nx.NetworkXError, G.remove_node, 1)
      pytest.raises(nx.NetworkXError, G.remove_nodes_from, [1])
      pytest.raises(nx.NetworkXError, G.add_edge, 1, 2)
      pytest.raises(nx.NetworkXError, G.add_edges_from, [(1, 2)])
      pytest.raises(nx.NetworkXError, G.remove_edge, 1, 2)
      pytest.raises(nx.NetworkXError, G.remove_edges_from, [(1, 2)])
      pytest.raises(nx.NetworkXError, G.clear_edges)
      pytest.raises(nx.NetworkXError, G.clear)
  
imports: import random
  import pytest
  import networkx
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 18 for calling the TestFunction obj's underlying member method code with example usage: obj.test_freeze() without return types