Exports of undefined variables

[djsegal]

I get the following variables as undefined:

• get_param_key
• show_statistics
• SGDSolverParameters

---

This lead me to wonder what the following lines do:

• https://github.com/pluskid/Mocha.jl/blob/611505d89a69102e0f4d2a870007f4d8540a8028/src/layers.jl#L17
• https://github.com/pluskid/Mocha.jl/blob/611505d89a69102e0f4d2a870007f4d8540a8028/src/layers.jl#L18
• https://github.com/pluskid/Mocha.jl/blob/d4a1774c389b5a47a383c24d2737c7c3eb620099/src/solvers/sgd-common.jl#L3

[pluskid]

Thanks for pointing this out! Those are legacy functions that we forgot to remove. I have fixed them now.