title: TensorFlow 2.0: do you need a @tf.function decorator on top of each function?
body: <p>In TensorFlow 2.0 (still alpha version right now) I know that you can use the decorator <code>@tf.function</code> in order to turn plain Python code into graph.
  Do I have to put <code>@tf.function</code> on top of each function for every time I want that? And is <code>@tf.function</code> considering just the following function block?</p>