code: def test_grid_motif():
      motif_generator = GridMotif()
      assert str(motif_generator) == "GridMotif()"
  
      motif = motif_generator()
      assert len(motif) == 3
      assert motif.num_nodes == 9
      assert motif.num_edges == 24
      assert motif.edge_index.size() == (2, 24)
      assert motif.edge_index.min() == 0
      assert motif.edge_index.max() == 8
      assert motif.y.size() == (9,)
      assert motif.y.min() == 0
      assert motif.y.max() == 2
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_grid_motif() without return types