Issue 1:
Environment info

transformers version:3.4.0

Platform:linux

Python version:3.6

PyTorch version (GPU?):1.6 cuda10

Tensorflow version (GPU?):

Using GPU in script?:

Using distributed or parallel set-up in script?:

When I try to train roberta-wwm from scratch for my dataset , I get this error when I follow transformers' run_mlm_wwm.py code

!python run_mlm_wwm.py --model_name_or_path hfl/chinese-roberta-wwm-ext --train_file ../../../../pretrain_data/pretrain_train.txt --validation_file ../../../../pretrain_data/pretrain_val.txt --train_ref_file ../../../../pretrain_data/ref_train.txt --validation_ref_file ../../../../pretrain_data/ref_val.txt --do_train --do_eval --output_dir ./output

All the weights of BertForMaskedLM were initialized from the model checkpoint at hfl/chinese-roberta-wwm-ext.
If your task is similar to the task the model of the checkpoint was trained on, you can already use BertForMaskedLM for predictions without further training.
Asking to truncate to max_length but no maximum length is provided and the model has no predefined maximum length. Default to no truncation.
Traceback (most recent call last):
File "run_mlm_wwm.py", line 333, in <module>
main()
File "run_mlm_wwm.py", line 274, in main
load_from_cache_file=not data_args.overwrite_cache,
File "/usr/local/lib/python3.6/dist-packages/datasets/dataset_dict.py", line 300, in map
for k, dataset in self.items()
File "/usr/local/lib/python3.6/dist-packages/datasets/dataset_dict.py", line 300, in <dictcomp>
for k, dataset in self.items()
File "/usr/local/lib/python3.6/dist-packages/datasets/arrow_dataset.py", line 1256, in map
update_data=update_data,
File "/usr/local/lib/python3.6/dist-packages/datasets/arrow_dataset.py", line 156, in wrapper
out: Union["Dataset", "DatasetDict"] = func(self, *args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/datasets/fingerprint.py", line 158, in wrapper
self._fingerprint, transform, kwargs_for_fingerprint
File "/usr/local/lib/python3.6/dist-packages/datasets/fingerprint.py", line 105, in update_fingerprint
hasher.update(transform_args[key])
File "/usr/local/lib/python3.6/dist-packages/datasets/fingerprint.py", line 57, in update
self.m.update(self.hash(value).encode("utf-8"))
File "/usr/local/lib/python3.6/dist-packages/datasets/fingerprint.py", line 53, in hash
return cls.hash_default(value)
File "/usr/local/lib/python3.6/dist-packages/datasets/fingerprint.py", line 46, in hash_default
return cls.hash_bytes(dumps(value))
File "/usr/local/lib/python3.6/dist-packages/datasets/utils/py_utils.py", line 367, in dumps
dump(obj, file)
File "/usr/local/lib/python3.6/dist-packages/datasets/utils/py_utils.py", line 339, in dump
Pickler(file, recurse=True).dump(obj)
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 454, in dump
StockPickler.dump(self, obj)
File "/usr/lib/python3.6/pickle.py", line 409, in dump
self.save(obj)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 1447, in save_function
obj.__dict__, fkwdefaults), obj=obj)
File "/usr/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/lib/python3.6/pickle.py", line 751, in save_tuple
save(element)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/lib/python3.6/pickle.py", line 736, in save_tuple
save(element)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 1178, in save_cell
pickler.save_reduce(_create_cell, (f,), obj=obj)
File "/usr/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/lib/python3.6/pickle.py", line 736, in save_tuple
save(element)
File "/usr/lib/python3.6/pickle.py", line 521, in save
self.save_reduce(obj=obj, *rv)
File "/usr/lib/python3.6/pickle.py", line 605, in save_reduce
save(cls)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 1374, in save_type
obj.__bases__, _dict), obj=obj)
File "/usr/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/lib/python3.6/pickle.py", line 751, in save_tuple
save(element)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 941, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python3.6/pickle.py", line 821, in save_dict
self._batch_setitems(obj.items())
File "/usr/lib/python3.6/pickle.py", line 847, in _batch_setitems
save(v)
File "/usr/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/lib/python3.6/dist-packages/dill/_dill.py", line 941, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/lib/python3.6/pickle.py", line 821, in save_dict
self._batch_setitems(obj.items())
File "/usr/lib/python3.6/pickle.py", line 847, in _batch_setitems
save(v)
File "/usr/lib/python3.6/pickle.py", line 507, in save
self.save_global(obj, rv)
File "/usr/lib/python3.6/pickle.py", line 927, in save_global
(obj, module_name, name))
**_pickle.PicklingError: Can't pickle typing.Union[str, NoneType]: it's not the same object as typing.Union**

please help me.

Issue 2:
While fine-tuning BERT with the new script I am facing the issue as follows:

Traceback (most recent call last):
File "run_mlm.py", line 310, in <module>
main()
File "run_mlm.py", line 259, in main
load_from_cache_file=not data_args.overwrite_cache,
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/dataset_dict.py", line 300, in map
for k, dataset in self.items()
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/dataset_dict.py", line 300, in <dictcomp>
for k, dataset in self.items()
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/arrow_dataset.py", line 1256, in map
update_data=update_data,
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/arrow_dataset.py", line 156, in wrapper
out: Union["Dataset", "DatasetDict"] = func(self, *args, **kwargs)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/fingerprint.py", line 158, in wrapper
self._fingerprint, transform, kwargs_for_fingerprint
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/fingerprint.py", line 105, in update_fingerprint
hasher.update(transform_args[key])
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/fingerprint.py", line 57, in update
self.m.update(self.hash(value).encode("utf-8"))
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/fingerprint.py", line 53, in hash
return cls.hash_default(value)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/fingerprint.py", line 46, in hash_default
return cls.hash_bytes(dumps(value))
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/utils/py_utils.py", line 367, in dumps
dump(obj, file)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/datasets/utils/py_utils.py", line 339, in dump
Pickler(file, recurse=True).dump(obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 446, in dump
StockPickler.dump(self, obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 409, in dump
self.save(obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 1438, in save_function
obj.__dict__, fkwdefaults), obj=obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 751, in save_tuple
save(element)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 736, in save_tuple
save(element)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 1170, in save_cell
pickler.save_reduce(_create_cell, (f,), obj=obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 736, in save_tuple
save(element)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 521, in save
self.save_reduce(obj=obj, *rv)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 605, in save_reduce
save(cls)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 1365, in save_type
obj.__bases__, _dict), obj=obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 610, in save_reduce
save(args)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 751, in save_tuple
save(element)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 933, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 821, in save_dict
self._batch_setitems(obj.items())
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 847, in _batch_setitems
save(v)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 476, in save
f(self, obj) # Call unbound method with explicit self
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/site-packages/dill/_dill.py", line 933, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 821, in save_dict
self._batch_setitems(obj.items())
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 847, in _batch_setitems
save(v)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 507, in save
self.save_global(obj, rv)
File "/home/ai-students/anaconda3/envs/env_nesara/lib/python3.6/pickle.py", line 927, in save_global
(obj, module_name, name))
_pickle.PicklingError: Can't pickle typing.Union[str, NoneType]: it's not the same object as typing.Union

I am trying to run the same script with the already mentioned wikitext dataset. However, I am not able to run it successfully due to the above mentioned error.

@sgugger Could you please help me resolve this error?