The way Layer functions work is in two steps: you invoke it as a “Layer” to “instantiate” it with the parameters you want. The return value of that function is the actual instantiated function. Then you call that function with inputs and outputs. Here’s a thread that discusses that general idea in more details.
It all worked for me but I don’t recall how many iterations it took me to get to that point. 
If the tests fail, that means your code is incorrect. Now we need to figure out why. This is all complicated enough that we probably can’t do it just by talking about issues in general. I will send you a DM and we can use that private thread to discuss the actual code. Stay tuned …