code: def test_lexicographic_product_null():
      null = nx.null_graph()
      empty10 = nx.empty_graph(10)
      K3 = nx.complete_graph(3)
      K10 = nx.complete_graph(10)
      P3 = nx.path_graph(3)
      P10 = nx.path_graph(10)
      # null graph
      G = nx.lexicographic_product(null, null)
      assert nx.is_isomorphic(G, null)
      # null_graph X anything = null_graph and v.v.
      G = nx.lexicographic_product(null, empty10)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(null, K3)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(null, K10)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(null, P3)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(null, P10)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(empty10, null)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(K3, null)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(K10, null)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(P3, null)
      assert nx.is_isomorphic(G, null)
      G = nx.lexicographic_product(P10, null)
      assert nx.is_isomorphic(G, null)
  
imports: import pytest
  import networkx
  from networkx.utils import edges_equal
label_desc: Use image node_id 14 for calling a global function with example usage: test_lexicographic_product_null() without return types