coding structure of gaussian noise layer

I want to create a special layer to add some special noise to the data.

But my matlab version is 2017b, I don't have the example " gaussianNoiseLayer.m".

That file should be located at (matlabroot, 'examples', 'nnet', 'main', 'gaussianNoiseLayer.m') in the matlab 2018b or 2018a version.

I really want to know the coding structure of adding noise layer.

If any kind-hearted person has installed the latest version of matlab, can you send a copy of this file to me?

email: [e-mail] thank you very much！！