text: 
  
  TITLE
  run_clm.py Issue | MODEL_FOR_CAUSAL_LM_MAPPING is None
  
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  9
  
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  When I use latest code of [run_clm.py](https://github.com/huggingface/transformers/blob/master/examples/language-modeling/run_clm.py), it raises the following issue:
  ```
  python run_clm.py \
      --model_name_or_path gpt2 \
      --train_file path_to_train_file \
      --validation_file path_to_validation_file \
      --do_train \
      --do_eval \
      --output_dir /tmp/test-clm
  ```
  
  ```
  Traceback (most recent call last):
    File "run_clm.py", line 51, in <module>
      MODEL_CONFIG_CLASSES = list(MODEL_FOR_CAUSAL_LM_MAPPING.keys())
  AttributeError: 'NoneType' object has no attribute 'keys'
  ```
  I checked and noticed that MODEL_FOR_CAUSAL_LM_MAPPING is None. Any suggestion?