message: Add a testable example to tf.math.maximum
diff: @@ -6,4 +6,12 @@ op {
  endpoint {
  name: "maximum"
  }
  + description: <<END
  +Example:
  +>>> x = tf.constant([0., 0., 0., 0.])
  +>>> y = tf.constant([-2., 0., 2., 5.])
  +>>> tf.math.maximum(x, y)
  +<tf.Tensor: shape=(4,), dtype=float32, numpy=array([0., 0., 2., 5.], dtype=float32)>
  +
  +END
  }
  