step!
	
function defined in module 
	FluxTraining
			step!(learner, phase::Phase, batch)
			Run one step of training for 
			learner on batch. Behavior is customized through 
			phase.
			This is a required method for custom 
			
			Phase
		
s to implement. To implement 
			step!, it is recommended you make use of 
	
			
			runstep to get begin and end events as well as proper handling of 
	
			
			CancelStepExceptions.
			See the implementations of 
	
			
			TrainingPhase and 
	
			
			ValidationPhase for reference.
There are
			5
			methods for FluxTraining.step!:
		
The following pages link back here:
Performant data pipelines, Variational autoencoders
training/lrfind.jl , FluxTraining.jl , callbacks/metrics.jl , training.jl