Multiprocessing windows error
```
from datasets import load_dataset

dataset = load_dataset('glue', 'mrpc', split='train')


updated_dataset = dataset.map(lambda example: {'sentence1': 'My sentence: ' + example['sentence1']}, num_proc=4)

```
As described here https://huggingface.co/blog/fine-tune-xlsr-wav2vec2

When using the num_proc argument on windows the whole Python environment crashes and hanging in loop.
For example at the map_to_array part.
An error occures because the cache file already exists and windows throws and error. After this the log crashes into an loop 
Multiprocessing windows error 
 As described here https://huggingface.co/blog/fine-tune-xlsr-wav2vec2

When using the num_proc argument on windows the whole Python environment crashes and hanging in loop.
For example at the map_to_array part.
An error occures because the cache file already exists and windows throws and error. After this the log crashes into an loop  
 ```
from datasets import load_dataset

dataset = load_dataset('glue', 'mrpc', split='train')


updated_dataset = dataset.map(lambda example: {'sentence1': 'My sentence: ' + example['sentence1']}, num_proc=4)

```