'NoneType' object is not iterable

[Gu718-git]

The following problems occurred during training

File "tools/train.py", line 286, in
main()
File "tools/train.py", line 275, in main
train_model(
File "/root/FlashOCC/mmdetection3d/mmdet3d/apis/train.py", line 344, in train_model
train_detector(
File "/root/FlashOCC/mmdetection3d/mmdet3d/apis/train.py", line 319, in train_detector
runner.run(data_loaders, cfg.workflow)
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmcv/runner/epoch_based_runner.py", line 130, in run
epoch_runner(data_loaders[i], **kwargs)
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmcv/runner/epoch_based_runner.py", line 51, in train
self.run_iter(data_batch, train_mode=True, **kwargs)
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmcv/runner/epoch_based_runner.py", line 29, in run_iter
outputs = self.model.train_step(data_batch, self.optimizer,
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmcv/parallel/data_parallel.py", line 75, in train_step
return self.module.train_step(*inputs[0], **kwargs[0])
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmdet/models/detectors/base.py", line 248, in train_step
losses = self(**data)
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/torch/nn/modules/module.py", line 1102, in _call_impl
return forward_call(*input, **kwargs)
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmcv/runner/fp16_utils.py", line 116, in new_func
return old_func(*args, **kwargs)
File "/root/FlashOCC/mmdetection3d/mmdet3d/models/detectors/base.py", line 60, in forward
return self.forward_train(**kwargs)
File "/root/FlashOCC/projects/mmdet3d_plugin/models/detectors/bevdet_occ.py", line 439, in forward_train
File "/root/FlashOCC/projects/mmdet3d_plugin/models/detectors/bevdet_occ.py", line 453, in forward_aux_centerness_train
File "/root/FlashOCC/projects/mmdet3d_plugin/models/dense_heads/bev_centerpoint_head.py", line 1404, in loss
heatmaps, anno_boxes, inds, masks = self.get_targets(
File "/root/FlashOCC/projects/mmdet3d_plugin/models/dense_heads/bev_centerpoint_head.py", line 1194, in get_targets
heatmaps, anno_boxes, inds, masks = multi_apply(
File "/root/miniconda3/envs/flashocc/lib/python3.8/site-packages/mmdet/core/utils/misc.py", line 29, in multi_apply
map_results = map(pfunc, *args)
TypeError: 'NoneType' object is not iterable