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 = UnitStep[#]*# + UnitStep[-#]*0.3# &;
    Plot[f[x], {x, -2, 2}]
    f[{-1, -0.5, 0, 0.5, 1}]

[![enter image description here][4]][4]

It also failed.

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

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

What about `PReLU`,`ELU`,`ThresholdedReLU`?

**Ps: Thank you @nikie**

`LeakyReLU` : `ElementwiseLayer[Ramp[#] - Ramp[-#]*0.3 &]`

`ELU` : `ElementwiseLayer[Ramp[#] - Ramp[-#]/#*(Exp[#] - 1) &]`


  [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/dLHdh.png
  [5]: https://i.sstatic.net/dV0om.png