diff --git a/src/layers/stateless.jl b/src/layers/stateless.jl
index 12523afe..76ade52c 100644
--- a/src/layers/stateless.jl
+++ b/src/layers/stateless.jl
@@ -1,7 +1,6 @@
 # Cost functions
 
 mse(ŷ, y) = sum((ŷ .- y).^2)/length(y)
-# back!(::typeof(mse), Δ, ŷ, y) = Δ .* (ŷ .- y)
 
-logloss(ŷ, y) = -sum(y .* log.(ŷ)) / size(y, 2)
-# back!(::typeof(logloss), Δ, ŷ, y) = 0 .- Δ .* y ./ ŷ
+logloss(ŷ::AbstractVecOrMat, y::AbstractVecOrMat) =
+  -sum(y .* log.(ŷ)) / size(y, 2)