sequence item 26: expected str instance, NoneType found

[win5923]

i use this model Transformers-Tutorials/Fine_tune_TrOCR_on_IAM_Handwriting_Database_using_Seq2SeqTrainer.ipynb at master · NielsRogge/Transformers-Tutorials · GitHub to train my dataset. but i got this issue.sequence item 26: expected str instance, NoneType found I only changed the path of the dataset. This problem will occur halfway through training. i don't know hot to fix it. I use TrOCR model. thx