message: Update docstring for tf.ensure_shape
  Update docstring
  Enhance example.
diff: @@ -2107,24 +2107,30 @@ def ensure_shape(x, shape, name=None):
  """Updates the shape of a tensor and checks at runtime that the shape holds.
  For example:
  - ```python
  - x = tf.compat.v1.placeholder(tf.int32)
  - print(x.shape)
  - ==> TensorShape(None)
  - y = x * 2
  - print(y.shape)
  - ==> TensorShape(None)
  +
  + >>> # tf.placeholder() is not compatible with eager execution
  + ...
  + >>> tf.compat.v1.disable_eager_execution()
  + >>> x = tf.compat.v1.placeholder(tf.int32)
  + >>> print(x.shape)
  + TensorShape(None)
  + >>> y = x * 2
  + >>> print(y.shape)
  + TensorShape(None)
  y = tf.ensure_shape(y, (None, 3, 3))
  print(y.shape)
  - ==> TensorShape([Dimension(None), Dimension(3), Dimension(3)])
  + TensorShape([None, 3, 3])
  - with tf.compat.v1.Session() as sess:
  - # Raises tf.errors.InvalidArgumentError, because the shape (3,) is not
  - # compatible with the shape (None, 3, 3)
  - sess.run(y, feed_dict={x: [1, 2, 3]})
  + >>> with tf.compat.v1.Session() as sess:
  + >>> sess.run(y, feed_dict={x: [1, 2, 3]})
  + Traceback (most recent call last):
  + ...
  + InvalidArgumentError: Shape of tensor mul [3] is not compatible with
  + expected shape [?,3,3].
  - ```
  + The above example raises `tf.errors.InvalidArgumentError`,
  + because the shape (3,) is not compatible with the shape (None, 3, 3)
  NOTE: This differs from `Tensor.set_shape` in that it sets the static shape
  of the resulting tensor and enforces it at runtime, raising an error if the
  @@ -2140,8 +2146,10 @@ def ensure_shape(x, shape, name=None):
  name: A name for this operation (optional). Defaults to "EnsureShape".
  Returns:
  - A `Tensor`. Has the same type and contents as `x`. At runtime, raises a
  - `tf.errors.InvalidArgumentError` if `shape` is incompatible with the shape
  + A `Tensor`. Has the same type and contents as `x`.
  +
  + Raises:
  + tf.errors.InvalidArgumentError: If `shape` is incompatible with the shape
  of `x`.
  """
  if not isinstance(shape, tensor_shape.TensorShape):
  