pip install -qU  momento langchain-openai langchain-community tiktoken

import getpass
import os

if "MOMENTO_API_KEY" not in os.environ:
    os.environ["MOMENTO_API_KEY"] = getpass.getpass("Momento API Key:")

if "OPENAI_API_KEY" not in os.environ:
    os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

from langchain_community.document_loaders import TextLoader
from langchain_community.vectorstores import MomentoVectorIndex
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter

loader = TextLoader("../../how_to/state_of_the_union.txt")
documents = loader.load()
len(documents)

1

len(documents[0].page_content)

38539

text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)
len(docs)

42

vector_db = MomentoVectorIndex.from_documents(
    docs, OpenAIEmbeddings(), index_name="sotu"
)

query = "What did the president say about Ketanji Brown Jackson"
docs = vector_db.similarity_search(query)

docs[0].page_content

'Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. \n\nTonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. \n\nOne of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. \n\nAnd I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.'

from langchain.chains import RetrievalQA
from langchain_openai import ChatOpenAI

llm = ChatOpenAI(model="gpt-3.5-turbo", temperature=0)
qa_chain = RetrievalQA.from_chain_type(llm, retriever=vector_db.as_retriever())

qa_chain({"query": "What did the president say about Ketanji Brown Jackson?"})

{'query': 'What did the president say about Ketanji Brown Jackson?',
 'result': "The President said that he nominated Circuit Court of Appeals Judge Ketanji Brown Jackson to serve on the United States Supreme Court. He described her as one of the nation's top legal minds and mentioned that she has received broad support from various groups, including the Fraternal Order of Police and former judges appointed by Democrats and Republicans."}