code: def on_backward_end(self, **kwargs):
          "accumulated step and reset samples, True will result in no stepping"
          if (self.acc_batches % self.n_step) == 0:
              for p in (self.learn.model.parameters()):
                  if p.requires_grad: p.grad.div_(self.acc_samples)
              self.acc_samples = 0
          else: return {'skip_step':True, 'skip_zero':Truef on_backward_end(self, **kwargs):
          "accumulated step and reset samples, True will result in no stepping"
          if (self.acc_batches % self.n_step) == 0:
              for p in (self.learn.model.parameters()):
                  if p.requires_grad: p.grad.div_(self.acc_samples)
              self.acc_samples = 0
          else: return {'skip_step':True, 'skip_zero':True}
docs: accumulated step and reset samples, True will result in no stepping