LEDForSequenceClassification and LEDForQuestionAnswering example codes don't work.
## Environment info
Tried on both transformers=4.2.0 and the latest transformer package.

### Who can help
@patrickvonplaten

Models:

LED

## Information

LEDForSequenceClassification and LEDForQuestionAnswering example code doesn't work. Please fix these bugs. LEDForConditionalGeneration works though. [here](https://huggingface.co/transformers/model_doc/led.html#ledforsequenceclassification)

The example [notebook](https://colab.research.google.com/drive/12LjJazBl7Gam0XBPy_y0CTOJZeZ34c2v?usp=sharing) only works for transformers=4.2.0. Specifically, there will be an error of in-place operation during the training. It will be helpful if you can update the code to adapt to the latest packages.
Actually we should probs just remove those examples since there is no fine-tuned model anyways...@jacklxc would you like to make a PR? :-)<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

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