pip install transformers not downloading gpt2-xl
Following the release of 1.5 B parameter model, I attempted to upgrade my version using the following command:

pip install transformers --upgrade


The installed library does not have gpt2-xl, and throws this error when I try calling it:

OSError: Model name 'gpt2-xl' was not found in model name list (gpt2, gpt2-medium, gpt2-large, distilgpt2). We assumed 'gpt2-xl' was a path or url to a configuration file named config.json or a directory containing such a file but couldn't find any such file at this path or url.

Please update the pip installer to allow the easy installation of the latest model
We haven't updated the pip version yet, we'll do so in the following weeks. Please install it from source in the meantime:

```
pip install git+https://github.com/huggingface/transformers
```<|||||>Traceback (most recent call last):
  File "run_pplm.py", line 936, in <module>
    run_pplm_example(**vars(args))
  File "run_pplm.py", line 738, in run_pplm_example
    tokenizer = GPT2Tokenizer.from_pretrained(pretrained_model)
  File "/home/xps/anaconda3/envs/nlg_entity/lib/python3.7/site-packages/transformers/tokenization_utils.py", line 911, in from_pretrained
    return cls._from_pr
etrained(*inputs, **kwargs)
  File "/home/xps/anaconda3/envs/nlg_entity/lib/python3.7/site-packages/transformers/tokenization_utils.py", line 1014, in _from_pretraine
    list(cls.vocab_files_names.values()),
OSError: Model name 'gpt2-medium' was not found in tokenizers model name list (gpt2, gpt2-medium, gpt2-large, gpt2-xl, distilgpt2). We asswas a path, a model identifier, or url to a directory containing vocabulary files named ['vocab.json', 'merges.txt'] but couldn't find sucat this path or url.




I also reported the same error....@LysandreJik
<|||||>> 回溯（最近一次调用）：
> 文件“run_pplm.py”，第 936 行，在
> run_pplm_example(**vars(args))
> 文件“run_pplm.py”，第 738 行，在 run_pplm_example
> tokenizer = GPT2Tokenizer.from_pretrained(pretrained_model)
> 文件“ /home/xps/anaconda3/envs/nlg_entity/lib/python3.7/site-packages/transformers/tokenization_utils.py", line 911, in from_pretrained
> return
> cls._from_pretrained(*inputs, **kwargs)
> File "/home /xps/anaconda3/envs/nlg_entity/lib/python3.7/site-packages/transformers/tokenization_utils.py”，第 1014 行，在 _from_pretraine
> 列表（cls.vocab_files_names.values()）中，
> OSError：在标记器模型名称列表（gpt2、gpt2-medium、gpt2-large、gpt2-xl、distlgpt2）中找不到模型名称“gpt2-medium”。我们为包含名为 ['vocab.json', 'merges.txt'] 的词汇文件的目录添加了路径、模型标识符或 url，但找不到此路径或 url。
> 
> 我也报了同样的错误.... @LysandreJik

hi,you can run this model?