code: def sparse_matrix_example(N=10, density=0.1):
      A = sps.rand(N, N, density=density, format="coo")
      A_indices = np.hstack((A.row[:, None], A.col[:, None]))
      A_values = A.data
      return A_indices, A_values, A
  
file_path: stellargraph/tests/layer/test_misc.py
imports: import tensorflow
  from tensorflow import keras
  import numpy
  import scipy.sparse
  import pytest
  from stellargraph.layer.misc import *
  from ..test_utils.graphs import create_graph_features, example_graph
  from stellargraph.mapper import *
  from stellargraph.layer import *
label_desc: Use image node_id 1 for calling a global function with example usage: sparse_matrix_example(N, density) and returns: A_indices,  A_values,  A