 AttributeError: 'NoneType' object has no attribute 'get'
I am facing issue when I train a tansformer LM, its giving attribute error  'NoneType' object has no attribute 'get. Please help me to resolve this
I have update the tansformer config file as given below

train_ds = "dummydata.txt"
vocab="vocab.txt"
config.model.train_ds.file_name =  train_ds
config.model.validation_ds.file_name =  train_ds
config.model.test_ds.file_name=train_ds
config.model.tokenizer.vocab_file=  vocab 
config.model.tokenizer.tokenizer_model= "tokenizer_spe_v2000"


AttributeError                            Traceback (most recent call last)
<ipython-input-43-cb4d43dca025> in <module>
      2 
      3 
----> 4 model = nemo_nlp.models.language_modeling.TransformerLMModel(cfg=config.model, trainer=trainer)
      5 

/opt/conda/lib/python3.6/site-packages/nemo/collections/nlp/models/language_modeling/transformer_lm_model.py in __init__(self, cfg, trainer)
     51         self.dataset_cfg = cfg.dataset
     52 
---> 53         vocab_file = cfg.language_model.get("vocab_file", None)
     54 
     55         if vocab_file is not None:

AttributeError: 'NoneType' object has no attribute 'get

