## Highlights

*   TF 2.0 delivers Keras as the central high level API used to build and train
    models. Keras provides several model-building APIs such as Sequential,
    Functional, and Subclassing along with eager execution, for immediate
    iteration and intuitive debugging, and `tf.data`, for building scalable
    input pipelines. Checkout
    [guide](https://www.tensorflow.org/beta/guide/keras/overview) for additional
    details.

The named axis labels may be any single character other than those having
special meaning, namely `,.->`. The behavior of this Op is undefined if it
receives an ill-formatted equation; since the validation is done at
graph-building time, we omit format validation checks at runtime.

Note: This Op is *not* intended to be called by the user; instead users should
call `tf.einsum` directly. It is a hidden Op used by `tf.einsum`.