ValueError: Default process group has not been initialized, please make sure to call init_process_group.

I'm Running into this problem on a Mac M3 Sonoma 15.5 and python 3.10.14

When trying to execute the simple example from the documentation for finetuning a model :
```python
from ragatouille import RAGTrainer
from ragatouille.utils import get_wikipedia_page
if __name__ == "__main__":
pairs = [
("What is the meaning of life ?", "The meaning of life is 42"),
("What is Neural Search?", "Neural Search is a terms referring to a family of ..."),
# You need many more pairs to train! Check the examples for more details!
...
]

my_full_corpus = [get_wikipedia_page("Hayao_Miyazaki"), get_wikipedia_page("Studio_Ghibli")]


trainer = RAGTrainer(model_name = "MyFineTunedColBERT",
pretrained_model_name = "colbert-ir/colbertv2.0") # In this example, we run fine-tuning

# This step handles all the data processing, check the examples for more details!
trainer.prepare_training_data(raw_data=pairs,
data_out_path="./data/",
all_documents=my_full_corpus)

trainer.train(batch_size=32) # Train with the default hyperparams
```
it's returning the following error :
```
ValueError: Default process group has not been initialized, please make sure to call init_process_group.
```
Seems to be an error due to paralling training but nothing that I'm sure of.

Reproduce the documented RAGTrainer example on the reported Mac M3, Python 3.10.14 environment, starting with RAGTrainer.train after prepare_training_data. Inspect the training entry point and the process-group setup involved in the reported ValueError. Done means the example can begin training without the uninitialized default process-group error, or the documentation clearly states the required setup.

Written by the indexing model from the issue text.