求解决增量学习模型训练代码问题

在训练模型的时候，有语句

 filename='model/accuracy:%.3f_KNN_accuracy:%.3f_increment:%d_net.pkl' % (accuracy, KNN_accuracy, i + 10)
torch.save(self.model,filename)

但在训练第2句的时候会出现错误

Traceback (most recent call last):
  File "/home/mist/miniconda3/main.py", line 20, in <module>
    model.afterTrain(accuracy)
  File "/home/mist/miniconda3/iCaRL.py", line 238, in afterTrain
    torch.save(self.model,filename)
  File "/usr/local/lib/python3.6/dist-packages/torch/serialization.py", line 361, in save
    with _open_file_like(f, 'wb') as opened_file:
  File "/usr/local/lib/python3.6/dist-packages/torch/serialization.py", line 229, in _open_file_like
    return _open_file(name_or_buffer, mode)
  File "/usr/local/lib/python3.6/dist-packages/torch/serialization.py", line 210, in __init__
    super(_open_file, self).__init__(open(name, mode))
FileNotFoundError: [Errno 2] No such file or directory: 'model/accuracy:83.800_KNN_accuracy:84.900_increment:19_net.pkl'

加./