message: Change TFStackTest to be Python3 compliant.
  From Python3.5, we have a different object to represent a FrameSummary:
diff: @@ -36,7 +36,7 @@ class TFStackTest(test.TestCase):
  def testConsistencyWithTraceback(self):
  stack, expected_stack = extract_stack()
  for frame, expected in zip(stack, expected_stack):
  - self.assertEqual(tuple(frame), expected)
  + self.assertEqual(convert_stack_frame(frame), expected)
  def testFormatStack(self):
  stack, expected_stack = extract_stack()
  @@ -58,5 +58,17 @@ def extract_stack(limit=None):
  return tf_stack.extract_stack(limit), traceback.extract_stack(limit)
  +def convert_stack_frame(frame):
  + """Converts a TF stack frame into Python's."""
  + # TODO(mihaimaruseac): Remove except case when dropping suport for py2
  + try:
  + return traceback.FrameSummary(
  + frame.filename, frame.lineno, frame.name, line=frame.line)
  + except AttributeError:
  + # On Python < 3.5 (i.e., Python2), we don't have traceback.FrameSummary so
  + # we don't need to match with that class. Instead, just a tuple is enough.
  + return tuple(frame)
  +
  +
  if __name__ == "__main__":
  test.main()
  