code: def testDAGPipelineInputAndOutputType(self):
      # Tests that the DAGPipeline has the correct `input_type` and
      # `output_type` values based on the DAG given to it.
      a, b, c, d = UnitA(), UnitB(), UnitC(), UnitD()
  
      dag = {
          a: dag_pipeline.DagInput(Type0),
          b: a["t1"],
          c: {"A_data": a["t2"], "B_data": b},
          d: {"0": c["regular_data"], "1": b, "2": c["special_data"]},
          dag_pipeline.DagOutput("abcdz"): d,
      }
      dag_pipe_obj = dag_pipeline.DAGPipeline(dag)
      self.assertEqual(dag_pipe_obj.input_type, Type0)
      self.assertEqual(dag_pipe_obj.output_type, {"abcdz": Type5})
  
      dag = {
          a: dag_pipeline.DagInput(Type0),
          dag_pipeline.DagOutput("t1"): a["t1"],
          dag_pipeline.DagOutput("t2"): a["t2"],
      }
      dag_pipe_obj = dag_pipeline.DAGPipeline(dag)
      self.assertEqual(dag_pipe_obj.input_type, Type0)
      self.assertEqual(
          dag_pipe_obj.output_type, {"t1": Type1, "t2": Type2}
      )
  
imports: import collections
  from absl.testing import absltest
  from magenta.pipelines import dag_pipeline
  from magenta.pipelines import pipeline
  from magenta.pipelines import statistics
label_desc: Use image node_id 1 for calling the DAGPipelineTest obj's underlying member method code with example usage: obj.testDAGPipelineInputAndOutputType() without return types