code: def on_train_begin(self, epoch:int, **kwargs:Any)->None:
          "Initialize the schedulers for training."
          res = {'epoch':self.start_epoch} if self.start_epoch is not None else None
          self.start_epoch = ifnone(self.start_epoch, epoch)
          self.scheds = [p.scheds for p in self.phases]
          self.opt = self.learn.opt
          for k,v in self.scheds[0].items(): 
              v.restart()
              self.opt.set_stat(k, v.start)
          self.idx_s = 0
          return ref on_train_begin(self, epoch:int, **kwargs:Any)->None:
          "Initialize the schedulers for training."
          res = {'epoch':self.start_epoch} if self.start_epoch is not None else None
          self.start_epoch = ifnone(self.start_epoch, epoch)
          self.scheds = [p.scheds for p in self.phases]
          self.opt = self.learn.opt
          for k,v in self.scheds[0].items(): 
              v.restart()
              self.opt.set_stat(k, v.start)
          self.idx_s = 0
          return res
docs: Initialize the schedulers for training.