get ValueError: too many values to unpack (expected 2) when run example command for training

[pingnuttakrid]

File "./mmdetection/tools/train.py", line 108, in
main()
File "./mmdetection/tools/train.py", line 104, in main
logger=logger)
File "/ping/ping/RepPoints/mmdetection/mmdet/apis/train.py", line 58, in train_detector
_dist_train(model, dataset, cfg, validate=validate)
File "/ping/ping/RepPoints/mmdetection/mmdet/apis/train.py", line 143, in _dist_train
for ds in dataset
File "/ping/ping/RepPoints/mmdetection/mmdet/apis/train.py", line 143, in
for ds in dataset
File "/ping/ping/RepPoints/mmdetection/mmdet/datasets/loader/build_loader.py", line 28, in build_dataloader
world_size, rank)
File "/ping/ping/RepPoints/mmdetection/mmdet/datasets/loader/sampler.py", line 97, in init
_rank, _num_replicas = get_host_info()
ValueError: too many values to unpack (expected 2)

get this error when run example command for training