StepBackQuery.py

from langchain.prompts import ChatPromptTemplate
from operator import itemgetter
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate, FewShotChatMessagePromptTemplate
from langchain_openai import ChatOpenAI
from langchain_core.runnables import RunnableLambda
from helper import get_retriever

def get_answer(link: str, question:str):
    examples = [
    {
    "input": "Could the members of The Police perform lawful arrests?",
    "output": "what can the members of The Police do?",
    },
    {
        "input": "Jan Sindel’s was born in what country?",
        "output": "what is Jan Sindel’s personal history?",
    },
    ]
    # We now transform these to example messages
    example_prompt = ChatPromptTemplate.from_messages(
        [
            ("human", "{input}"),
            ("ai", "{output}"),
        ]
    )
    few_shot_prompt = FewShotChatMessagePromptTemplate(
        example_prompt=example_prompt,
        examples=examples,
    )
    prompt = ChatPromptTemplate.from_messages(
        [
            (
                "system",
                """You are an expert at world knowledge. Your task is to step back and paraphrase a question to a more generic step-back question, which is easier to answer. Here are a few examples:""",
            ),
            # Few shot examples
            few_shot_prompt,
            # New question
            ("user", "{question}"),
        ]
    )

    generate_queries_step_back = (
        prompt |
        ChatOpenAI(temperature=0) |
        StrOutputParser()
    )
    # question = "What is task decomposition for LLM agents?"
    generate_queries_step_back.invoke({"question": question})   

    # Response prompt 
    response_prompt_template = """You are an expert of world knowledge. I am going to ask you a question. Your response should be comprehensive and not contradicted with the following context if they are relevant. Otherwise, ignore them if they are not relevant.

    # {normal_context}
    # {step_back_context}

    # Original Question: {question}
    # Answer:"""
    response_prompt = ChatPromptTemplate.from_template(response_prompt_template)
    retrievar = get_retriever(link)
    chain = (
        {
            # Retrieve context using the normal question
            "normal_context": RunnableLambda(lambda x: x["question"]) | retrievar,
            # Retrieve context using the step-back question
            "step_back_context": generate_queries_step_back | retrievar,
            # Pass on the question
            "question": lambda x: x["question"],
        }
        | response_prompt
        | ChatOpenAI(temperature=0)
        | StrOutputParser()
    )

    response = chain.invoke({"question": question})
    return response


# if __name__ == "__main__":
#     link = "https://lilianweng.github.io/posts/2023-06-23-agent/"
#     question = "What is task decomposition for LLM agents?"
#     answer = get_answer(link, question)
#     print(answer)