from transformers import GPT2Tokenizer
proxies = {'http':'http://my.proxy.com:port', 'https':'https://my.proxy.com:port'}
tokenizer = GPT2Tokenizer.from_pretrained("gpt2", proxies=proxies)

from transformers import GPT2LMHeadModel
proxies = {'http':'http://my.proxy.com:port', 'https':'https://my.proxy.com:port'}
model = GPT2LMHeadModel.from_pretrained("gpt2", proxies=proxies)

Traceback (most recent call last):
  File "/path/to/anaconda3/lib/python3.7/site-packages/transformers/modeling_utils.py", line 638, in from_pretrained
    raise EnvironmentError
OSError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/path/to/text_gen_w_transformers/finetune_test.py", line 28, in <module>
    model = GPT2LMHeadModel.from_pretrained("gpt2", proxies=proxies)
  File "/path/to/anaconda3/lib/python3.7/site-packages/transformers/modeling_utils.py", line 645, in from_pretrained
    raise EnvironmentError(msg)
OSError: Can't load weights 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 file named one of pytorch_model.bin, tf_model.h5, model.ckpt.