TypeError: Caught TypeError in DataLoader worker process 0.

[EslamHaourn]

log file path:log/log_2023-11-01_18-25-54.txt
2023-11-01 18:25:54,478 train.py[line:619] INFO: Using device cuda
2023-11-01 18:25:57,571 train.py[line:318] INFO: Starting training:
Epochs: 100
Batch size: 16
Subdivisions: 16
Learning rate: 0.001
Training size: 4488
Validation size: 1476
Checkpoints: True
Device: cuda
Images size: 512
Optimizer: adam
Dataset classes: 6
Train label path:train.txt
Pretrained:

Epoch 1/100: 0%| | 0/4488 [00:00<?, ?img/s]
Traceback (most recent call last):
File "train.py", line 631, in
train(model=model,
File "train.py", line 375, in train
for i, batch in enumerate(train_loader):
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 517, in next
data = self._next_data()
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 1199, in _next_data
return self._process_data(data)
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 1225, in _process_data
data.reraise()
File "/home/eslam/.local/lib/python3.8/site-packages/torch/_utils.py", line 429, in reraise
raise self.exc_type(msg)
TypeError: Caught TypeError in DataLoader worker process 0.
Original Traceback (most recent call last):
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/_utils/worker.py", line 202, in _worker_loop
data = fetcher.fetch(index)
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/_utils/fetch.py", line 44, in fetch
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/home/eslam/.local/lib/python3.8/site-packages/torch/utils/data/_utils/fetch.py", line 44, in
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/home/eslam/pytorch-YOLOv4-master/dataset.py", line 274, in getitem
img_path = os.path.join(self.cfg.dataset_dir, img_path)
File "/usr/lib/python3.8/posixpath.py", line 76, in join
a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not NoneType

[EslamHaourn]

Hello,
This error prevent training to start. Could you help me know the mistake I do? kindly, help me. Any help would be appreciated.
Thanks in advance.