code: def test_sigma():
      Gs = nx.connected_watts_strogatz_graph(50, 6, 0.1, seed=rng)
      Gr = nx.connected_watts_strogatz_graph(50, 6, 1, seed=rng)
      sigmas = sigma(Gs, niter=1, nrand=2, seed=rng)
      sigmar = sigma(Gr, niter=1, nrand=2, seed=rng)
      assert sigmar < sigmas
  
file_path: networkx/networkx/algorithms/tests/test_smallworld.py
imports: import pytest
  import random
  import networkx
  from networkx import lattice_reference, omega, random_reference, sigma
label_desc: Use image node_id 3 for calling a global function with example usage: test_sigma() without return types