[bug]BertAdam change to AdamW in example
https://github.com/huggingface/pytorch-transformers/blob/master/examples/lm_finetuning/simple_lm_finetuning.py#L35  BertAdam change to AdamW
Changing that line still causes an error in line 568, BertAdam has to be changed to AdamW as well and the warmup kwarg has to be removed.<|||||>#797 (specifically d6522e28732fd14a926440ef5f315e6a8e13792c) <|||||>have fix the error! I tested it on toy dataset.<|||||>@shibing624   this bug can be closed