I’m trying to replicate part of the transformers tutorial from fastai, and there is a place one writes:
from transformers import GPT2LMHeadModel, GPT2TokenizerFast
pretrained_weights = 'gpt2'
tokenizer = GPT2TokenizerFast.from_pretrained(pretrained_weights)
model = GPT2LMHeadModel.from_pretrained(pretrained_weights)

However, trying to run it I get
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-31-b475580d46e5> in <module>
      1 from transformers import GPT2LMHeadModel, GPT2TokenizerFast
      2 pretrained_weights = 'gpt2'
----> 3 tokenizer = GPT2TokenizerFast.from_pretrained(pretrained_weights)
      4 model = GPT2LMHeadModel.from_pretrained(pretrained_weights)

/opt/conda/lib/python3.7/site-packages/transformers/tokenization_utils_base.py in from_pretrained(cls, pretrained_model_name_or_path, *init_inputs, **kwargs)
   1589                     ", ".join(s3_models),
   1590                     pretrained_model_name_or_path,
-> 1591                     list(cls.vocab_files_names.values()),
   1592                 )
   1593             )

OSError: Model name 'gpt2' was not found in tokenizers model name list (gpt2, gpt2-medium, gpt2-large, gpt2-xl, distilgpt2). We assumed 'gpt2' was a path, a model identifier, or url to a directory containing vocabulary files named ['vocab.json', 'merges.txt', 'tokenizer.json'] but couldn't find such vocabulary files at this path or url.


I find this confusing because gpt2 is in the list. In fact, I encounter the same problem with any transformer model I choose, like for instance distilgpt2 or from another family. In fact, if I comment out that line I also get an error
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
/opt/conda/lib/python3.7/site-packages/transformers/configuration_utils.py in get_config_dict(cls, pretrained_model_name_or_path, **kwargs)
    372             if resolved_config_file is None:
--> 373                 raise EnvironmentError
    374             config_dict = cls._dict_from_json_file(resolved_config_file)

OSError: 

During handling of the above exception, another exception occurred:

OSError                                   Traceback (most recent call last)
<ipython-input-32-a4869c5495d6> in <module>
      2 pretrained_weights = 'gpt2'
      3 #tokenizer = GPT2TokenizerFast.from_pretrained(pretrained_weights)
----> 4 model = GPT2LMHeadModel.from_pretrained(pretrained_weights)

/opt/conda/lib/python3.7/site-packages/transformers/modeling_utils.py in from_pretrained(cls, pretrained_model_name_or_path, *model_args, **kwargs)
    874                 proxies=proxies,
    875                 local_files_only=local_files_only,
--> 876                 **kwargs,
    877             )
    878         else:

/opt/conda/lib/python3.7/site-packages/transformers/configuration_utils.py in from_pretrained(cls, pretrained_model_name_or_path, **kwargs)
    327 
    328         """
--> 329         config_dict, kwargs = cls.get_config_dict(pretrained_model_name_or_path, **kwargs)
    330         return cls.from_dict(config_dict, **kwargs)
    331 

/opt/conda/lib/python3.7/site-packages/transformers/configuration_utils.py in get_config_dict(cls, pretrained_model_name_or_path, **kwargs)
    380                 f"- or '{pretrained_model_name_or_path}' is the correct path to a directory containing a {CONFIG_NAME} file\n\n"
    381             )
--> 382             raise EnvironmentError(msg)
    383 
    384         except json.JSONDecodeError:

OSError: Can't load config for 'gpt2'. Make sure that:

- 'gpt2' is a correct model identifier listed on 'https://huggingface.co/models'

- or 'gpt2' is the correct path to a directory containing a config.json file

Everything is run on Kaggle notebooks, in case it’s important
Thanks in advance!