Why is there not a SequenceClassification model for GPT-2?
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Why isn't there a SequenceClassificationModel (like there is for BERT) for GPT-2? I was able to implement this pretty easily by adding a "[CLS]" token to the vocabulary (like in the GPT2DoubleHeadsModel), appending sequences with "[CLS]", and then adding a linear layer that maps from the embedding of "[CLS]" to a vector of logits corresponding to the classes. After training, this model worked comparably to BertSequenceClassificationModel for my use-case. It would be nice to have this model in the transformers library and not have to code it up from scratch. 

If this sounds like a good idea, I can make a pull request with a GPT2SequenceClassificationModel added. If not, why is it not a good idea? 

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**A link to original question on Stack Overflow**: 
My apologies, my computer glitched and posted twice. Please close this issue and refer to: https://github.com/huggingface/transformers/issues/3600