transformers safetensors llama text-generation conversational th en dataset:HuggingFaceH4/ultrachat_200k dataset:HuggingFaceH4/ultrafeedback_binarized dataset:HuggingFaceH4/cai-conversation-harmless arxiv:2404.05829 license:llama2 model-index autotrain_compatible text-generation-inference endpoints_compatible region:us