code: def test_topsorted_layers_empty(self):
      layers = topsort.topsorted_layers(
          nodes=[],
          get_node_id_fn=lambda n: n.name,
          get_parent_nodes=lambda n: [],
          get_child_nodes=lambda n: [],
      )
      self.assertEqual([], layers)
  
file_path: tfx/tfx/utils/topsort_test.py
imports: import attr
  import tensorflow
  from tfx.utils import topsort
label_desc: Use image node_id 7 for calling the TopsortTest obj's underlying member method code with example usage: obj.test_topsorted_layers_empty() without return types