Remove redundant code

Author: foldfelis

example/FlowOverCircle/src/FlowOverCircle.jl

@@ -54,24 +54,6 @@ function get_dataloader(; ts::AbstractRange = LinRange(100, 11000, 10000),
     return loader_train, loader_test
 end
 
-function FluxTraining.step!(learner, phase::FluxTraining.TrainingPhase, batch)
-    xs, ys = batch
-    FluxTraining.runstep(learner, phase, (; xs = xs, ys = ys)) do handle, state
-        state.grads = FluxTraining._gradient(learner.optimizer, learner.model, learner.params) do model
-            state.ŷs = model(state.xs)
-            handle(FluxTraining.LossBegin())
-            state.loss = learner.lossfn(state.ŷs, state.ys)
-            handle(FluxTraining.BackwardBegin())
-
-            return state.loss
-        end
-
-        handle(FluxTraining.BackwardEnd())
-        learner.params, learner.model = FluxTraining._update!(
-            learner.optimizer, learner.params, learner.model, state.grads)
-    end
-end
-
 function train(; cuda = true, η₀ = 1.0f-3, λ = 1.0f-4, epochs = 50)
     if cuda && CUDA.has_cuda()
         device = gpu