code: def combined_cos(pct, start, middle, end):
      "Return a scheduler with cosine annealing from `start`→`middle` & `middle`→`end`"
      return combine_scheds(
          [pct, 1 - pct],
          [SchedCos(start, middle), SchedCos(middle, end)],
      )
  
imports: from __future__ import annotations
  from ..basics import *
  from .tracker import SaveModelCallback
label_desc: Use image node_id 12 for calling a global function with example usage: combined_cos(pct, start, middle, end) and returns: combine_scheds