peft safetensors mixtral dpo-experiment generated_from_trainer trl sft dataset:HuggingFaceH4/ultrachat_200k base_model:mistralai/Mixtral-8x7B-v0.1 base_model:adapter:mistralai/Mixtral-8x7B-v0.1 license:apache-2.0 4-bit bitsandbytes region:us