private setschedules! — function
setschedules!(learner, phase, schedules...)
Set schedules on learner’s Scheduler callback so that training resumes
from there.
If learner does not have a Scheduler callback yet, adds it.
learner = ...
fit!(learner, 1)
setschedules!(learner, onecycle(1, 0.01))
fit!(learner, 1)