code: def test_empty_graphs():
      for k in range(5, 25, 5):
          G = nx.empty_graph(k)
          assert 0 == approx.node_connectivity(G)
          assert 0 == approx.node_connectivity(G, 0, 3)
  
imports: import pytest
  import networkx
  from networkx.algorithms import approximation
label_desc: Use image node_id 4 for calling a global function with example usage: test_empty_graphs() without return types