message: Update parse_entity error message.
  `tf.autograph.do_not_convert` is still in `experimental` (as of `2.6.0.dev20210522`).
diff: @@ -155,11 +155,12 @@ def parse_entity(entity, future_features):
  except (IOError, OSError) as e:
  raise ValueError(
  'Unable to locate the source code of {}. Note that functions defined'
  - ' in certain environments, like the interactive Python shell do not'
  - ' expose their source code. If that is the case, you should to define'
  + ' in certain environments, like the interactive Python shell, do not'
  + ' expose their source code. If that is the case, you should define'
  ' them in a .py source file. If you are certain the code is'
  ' graph-compatible, wrap the call using'
  - ' @tf.autograph.do_not_convert. Original error: {}'.format(entity, e))
  + ' @tf.autograph.experimental.do_not_convert. Original error: {}'
  + .format(entity, e))
  source = dedent_block(original_source)
  