code: def test_concatenate2(n=10):
      G1 = complete_graph(n)
      G2 = complete_graph(n)
      G = concatenate_graphs(G1, G2)
      assert G.cc().max() == 1
  
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 39 for calling a global function with example usage: test_concatenate2(n) without return types