半监督训练的时候报错，错误如下

[HtAgoni]

 Epoch   gpu_mem    labels  img_size       box       obj       cls      loss    ss_box    ss_obj    ss_cls        tp    fp_cls    fp_loc   pse_num    gt_num
 27/45     10.1G        33       640   0.03321   0.01326   0.00238    0.3907    0.0272  0.004985  0.001648    0.8537         0    0.4029     1.072    0.9201: 100%|#| 66Traceback (most recent call last):

File "train.py", line 84, in main(opt) File "train.py", line 76, in main trainer.train(callbacks, val) File "/root/autodl-tmp/semi/5-efficientteacher/trainer/trainer.py", line 536, in train self.after_epoch(callbacks, val) File "/root/autodl-tmp/semi/5-efficientteacher/trainer/ssod_trainer.py", line 329, in after_epoch self.semi_ema.update_decay(self.epoch - self.cfg.hyp.burn_epochs) AttributeError: 'NoneType' object has no attribute 'update_decay'