class_docstr: Tests of GraphAttentionSparse layer
class_docstr_tok: ["Tests","of","GraphAttentionSparse","layer"]
code: def get_matrix(self, edges=[]):
      # adjacency matrix with self-loops + edges
      A_sparse = sps.eye(self.N, format="lil")
      for e, v in edges:
          A_sparse[e[0], e[1]] = v
      # Extract indices & values to feed to tensorflow
      A_sparse = A_sparse.tocoo()
      A_indices = np.expand_dims(
          np.hstack((A_sparse.row[:, None], A_sparse.col[:, None])), 0
      )
      A_values = np.expand_dims(A_sparse.data, 0)
      return [A_indices, A_values]
  
imports: import pytest
  import scipy.sparse
  import tensorflow
  from tensorflow import keras
  from tensorflow.keras import backend
  from tensorflow.keras.layers import Input
  from stellargraph.mapper import FullBatchNodeGenerator, FullBatchLinkGenerator, GraphSAGENodeGenerator
  from stellargraph.layer import *
  from ..test_utils.graphs import example_graph
  from ..None import test_utils
label_desc: Use image node_id 2 for calling the Test_GraphAttentionSparse obj's underlying member method code with example usage: obj.get_matrix(edges) and returns: list