Warning: Detected call of `lr_scheduler.step()` before `optimizer.step()`

[qingchen]

I encounter this warning when using the original code, but the code appears to call the optimizer first and then the scheduler.Has anyone else encountered this warning?
UserWarning: Detected call of lr_scheduler.step() before optimizer.step(). In PyTorch 1.1.0 and later, you should call them in the opposite order: optimizer.step() before lr_scheduler.step(). Failure to do this will result in PyTorch skipping the first value of the learning rate schedule. See more details at https://pytorch.org/docs/stable/optim.html#how-to-adjust-learning-rate
warnings.warn("Detected call of lr_scheduler.step() before optimizer.step(). "

Code in main.py:

        # student network     
        s_scaler.scale(s_loss).backward()
        if args.grad_clip > 0:
            s_scaler.unscale_(s_optimizer)
            nn.utils.clip_grad_norm_(student_model.parameters(), args.grad_clip)
        s_scaler.step(s_optimizer)
        s_scaler.update()
        s_scheduler.step()
        if args.ema > 0:
            avg_student_model.update_parameters(student_model)
        
        #teacher network
        t_scaler.scale(t_loss).backward()
        if args.grad_clip > 0:
            t_scaler.unscale_(t_optimizer)
            nn.utils.clip_grad_norm_(teacher_model.parameters(), args.grad_clip)
        t_scaler.step(t_optimizer)
        t_scaler.update()
        t_scheduler.step()

        teacher_model.zero_grad()
        student_model.zero_grad()