yolov3_spp运行报错，运行到datasets.py中line259报错：

[xin1347764176]

System information

• Have I written custom code:
• OS Platform(e.g., window10 or Linux Ubuntu 16.04):
• Python version:
• Deep learning framework and version(e.g., Tensorflow2.1 or Pytorch1.3):
• Use GPU or not:
• CUDA/cuDNN version(if you use GPU):
• The network you trained(e.g., Resnet34 network):

Describe the current behavior

Error info / logs