I want to try  [LeakyReLU Layer][1] in `Mathematica`,but not found.

In `keras`,the `LeakyReLU` be defined like this:

[![enter image description here][2]][2]

So I try to use `ElementwiseLayer` to implement it.

    g = Function[x, Piecewise[{{0.3(*default value*)*x, x < 0}, {x, x >= 0}}], Listable];
    Plot[g[x], {x, -2, 2}]
    g[{-1, -0.5, 0, 0.5, 1}]

[![enter image description here][3]][3]

But `ElementwiseLayer[g]` failed.

Then I try:

    f = HeavisideTheta[#]*# + HeavisideTheta[-#]*0.3# &;
    f[{-1, -0.5, 0, 0.5, 1}]



[![But `ElementwiseLayer\[f\]` also failed][4]][4].

[![enter image description here][5]][5]

It also failed,so it's confused me, how to make LeakyReLU or other advanced activations layers in Mathematica?


  [1]: https://keras.io/layers/advanced-activations/
  [2]: https://i.sstatic.net/87brz.png
  [3]: https://i.sstatic.net/8M9Z8.png
  [4]: https://i.sstatic.net/nEfC5.png
  [5]: https://i.sstatic.net/8QJ59.png