python-dotenv langchain==0.2.1 langchain-core==0.2.0 langchain-community==0.2.4 text-generation pypdf pymupdf gradio==4.44.1 faiss-cpu chromadb rank-bm25 spacy unstructured unstructured[pdf,xml] pdfminer.six tiktoken openai langchain-openai https://github.com/explosion/spacy-models/releases/download/en_core_web_sm-3.7.1/en_core_web_sm-3.7.1.tar.gz sentence-transformers langchain-groq tavily-python==0.3.3 ragas langchain-mistralai langchain_huggingface faiss-cpu nltk