base class.

## Major Features and Improvements

*   `tf.lite`:

    *   New operations supported:
          * tf.unsortedsegmentmin op is supported.
          * tf.atan2 op is supported.
          * tf.sign op is supported.
    *   Updates to existing operations:
          * tfl.mul now supports complex32 inputs.

*   `tf.experimental.StructuredTensor`

A method invocation is similar but the method itself
is specified as a selector upon a value of the receiver type for
the method.
</p>

<pre>
math.Atan2(x, y)  // function call
var pt *Point
pt.Scale(3.5)     // method call with receiver pt
</pre>

<p>
If <code>f</code> denotes a generic function, it must be

pkg math, func Acos(float64) float64
pkg math, func Acosh(float64) float64
pkg math, func Asin(float64) float64
pkg math, func Asinh(float64) float64
pkg math, func Atan(float64) float64
pkg math, func Atan2(float64, float64) float64
pkg math, func Atanh(float64) float64
pkg math, func Cbrt(float64) float64
pkg math, func Ceil(float64) float64
pkg math, func Copysign(float64, float64) float64