code: def test_copy():
      """test that the weighted graph copy is OK"""
      x = basicdata()
      G = cross_knn(x, x, 2)
      K = G.copy()
      assert K.edges.shape == (20, 2)
  
file_path: nipy/nipy/algorithms/graph/tests/test_bipartite_graph.py
imports: import numpy
  import numpy.random
  from ..bipartite_graph import check_feature_matrices, cross_eps, cross_knn
label_desc: Use image node_id 6 for calling a global function with example usage: test_copy() without return types