code: def test_k_is_3():
      G = nx.Graph(
          [
              (1, 6),
              (1, 7),
              (1, 8),
              (1, 9),
              (2, 6),
              (2, 7),
              (2, 8),
              (2, 10),
              (3, 6),
              (3, 8),
              (3, 9),
              (3, 10),
              (4, 7),
              (4, 8),
              (4, 9),
              (4, 10),
              (5, 6),
              (5, 7),
              (5, 9),
              (5, 10),
          ]
      )
      assert nx.bipartite.maximal_extendability(G) == 3
  
file_path: networkx/networkx/algorithms/bipartite/tests/test_extendability.py
imports: import pytest
  import networkx
label_desc: Use image node_id 7 for calling a global function with example usage: test_k_is_3() without return types