Error: 'GPT2Model' object has no attribute '_step' when converting tf-based checkpoint into pytorch
I'm trying to convert a tensorflow-based GPT-2 checkpoint into pytorch using `convert_gpt2_checkpoint_to_pytorch`, and get errors like:
```
INFO:transformers.modeling_gpt2:Converting TensorFlow checkpoint from /content/model.ckpt-220000
INFO:transformers.modeling_gpt2:Loading TF weight global_step with shape []
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/LayerNorm_embed_norm/beta with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/LayerNorm_embed_norm/beta/adafactor_v with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/LayerNorm_embed_norm/gamma with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/LayerNorm_embed_norm/gamma/adafactor_v with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/pos_embed with shape [1024, 1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/pos_embed/adafactor_vc with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/pos_embed/adafactor_vr with shape [1024]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/word_embed with shape [8021, 1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/word_embed/adafactor_vc with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/embeddings/word_embed/adafactor_vr with shape [8021]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer00/LayerNorm_mlp_ln0/beta with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer00/LayerNorm_mlp_ln0/beta/adafactor_v with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer00/LayerNorm_mlp_ln0/gamma with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer00/LayerNorm_mlp_ln0/gamma/adafactor_v with shape [1536]
...
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer47/value_layer/bias/adafactor_v with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer47/value_layer/kernel with shape [1536, 1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer47/value_layer/kernel/adafactor_vc with shape [1536]
INFO:transformers.modeling_gpt2:Loading TF weight newslm/layer47/value_layer/kernel/adafactor_vr with shape [1536]
---------------------------------------------------------------------------
ModuleAttributeError                      Traceback (most recent call last)
<ipython-input-38-45b704eacf86> in <module>()
      1 from transformers.convert_gpt2_original_tf_checkpoint_to_pytorch import convert_gpt2_checkpoint_to_pytorch
----> 2 convert_gpt2_checkpoint_to_pytorch('./model.ckpt-220000', '', 'pytorch')

2 frames
/usr/local/lib/python3.6/dist-packages/torch/nn/modules/module.py in __getattr__(self, name)
    770                 return modules[name]
    771         raise ModuleAttributeError("'{}' object has no attribute '{}'".format(
--> 772             type(self).__name__, name))
    773 
    774     def __setattr__(self, name: str, value: Union[Tensor, 'Module']) -> None:

ModuleAttributeError: 'GPT2Model' object has no attribute '_step'
```
It seems that the program cannot convert `global_step` layer into pytorch. Is there any solution to this?

same problem<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
