def on_after_backward(self, training_step_output, batch_idx, untouched_loss):
    training_step_output.detach()
    self.trainer.call_hook('on_after_backward')
    self.trainer.dev_debugger.track_train_loss_history(batch_idx, untouched_loss.detach())
def on_after_backward(self, training_step_output, batch_idx, untouched_loss):
    training_step_output.detach()
    self.trainer.call_hook('on_after_backward')
    self.trainer.dev_debugger.track_train_loss_history(batch_idx, untouched_loss.detach())