message: Update testable docstring.
  Sort the dict to make sure the ordering of the output.
diff: @@ -161,9 +161,9 @@ class FunctionalPreprocessingStage(base_preprocessing_layer.PreprocessingLayer,
  >>> stage = FunctionalPreprocessingStage(inputs, outputs)
  >>> ds = tf.data.Dataset.from_tensor_slices({'x1': tf.ones((4,5)),
  ... 'x2': tf.ones((4,1))})
  - >>> ds.element_spec # Check element_spec
  - {'x1': TensorSpec(shape=(5,), dtype=tf.float32, name=None),
  - 'x2': TensorSpec(shape=(1,), dtype=tf.float32, name=None)}
  + >>> sorted(ds.element_spec.items()) # Check element_spec
  + [('x1', TensorSpec(shape=(5,), dtype=tf.float32, name=None)),
  + ('x2', TensorSpec(shape=(1,), dtype=tf.float32, name=None))]
  >>> stage.adapt(ds)
  >>> data_np = {'x1': np.ones((4, 5)), 'x2': np.ones((4, 1))}
  >>> stage.adapt(data_np)
  