code: def testSimpleTimeline(self):
      run_options = config_pb2.RunOptions(
          trace_level=config_pb2.RunOptions.FULL_TRACE
      )
      run_metadata = config_pb2.RunMetadata()
  
      with ops.device("/cpu:0"):
          with session.Session() as sess:
              sess.run(
                  constant_op.constant(1.0),
                  options=run_options,
                  run_metadata=run_metadata,
              )
      self.assertTrue(run_metadata.HasField("step_stats"))
      tl = timeline.Timeline(run_metadata.step_stats)
      ctf = tl.generate_chrome_trace_format()
      self._validateTrace(ctf)
  
file_path: tensorflow-upstream/tensorflow/python/client/timeline_test.py
imports: import json
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.client import session
  from tensorflow.python.client import timeline
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import test_util
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the TimelineTest obj's underlying member method code with example usage: obj.testSimpleTimeline() without return types