code: def test_cc():
      G = basic_graph()
      l = G.cc()
      L = np.array(l == 0)
      assert L.all()
  
imports: import numpy
  import numpy.random
  from numpy.testing import assert_almost_equal, assert_array_almost_equal, assert_array_equal
  from ..graph import WeightedGraph, complete_graph, concatenate_graphs, eps_nn, knn, mst, wgraph_from_3d_grid, wgraph_from_adjacency, wgraph_from_coo_matrix
label_desc: Use image node_id 25 for calling a global function with example usage: test_cc() without return types