我正在尝试使用loadQAChain与自定义提示符。创建链的代码如下所示：

import { OpenAI } from 'langchain/llms/openai';
import { PineconeStore } from 'langchain/vectorstores/pinecone';
import { LLMChain, loadQAChain, ChatVectorDBQAChain } from 'langchain/chains';
import { PromptTemplate } from 'langchain/prompts';

const CONDENSE_PROMPT =
  PromptTemplate.fromTemplate(`Given the following conversation and a follow up question, rephrase the follow up question to be a standalone question.

Chat History:
{chat_history}
Follow Up Input: {question}
Standalone question:`);

const QA_PROMPT =
  PromptTemplate.fromTemplate(`You are a helpful AI assistant. Use the following pieces of context to answer the question at the end.
If you don't know the answer, just say you don't know. DO NOT try to make up an answer.
If the question is not related to the context, politely respond that you are tuned to only answer questions that are related to the context.

{context}

Question: {question}
Helpful answer in markdown:`);

export const makeChain = (vectorstore: PineconeStore) => {
  const questionGenerator = new LLMChain({
    llm: new OpenAI({ temperature: 0 }),
    prompt: CONDENSE_PROMPT,
  });
  const docChain = loadQAChain(
    //change modelName to gpt-4 if you have access to it
    new OpenAI({ temperature: 0, modelName: 'gpt-3.5-turbo' }),
    {
      prompt: QA_PROMPT,
    }
  );

  return new ChatVectorDBQAChain({
    vectorstore,
    combineDocumentsChain: docChain,
    questionGeneratorChain: questionGenerator,
    returnSourceDocuments: true,
    k: 4, //number of source documents to return. Change this figure as required.
  });
};

每当我从API Route调用makeChain时，Next.js中都会出现以下错误。

error Error: Invalid _type: undefined
    at loadQAChain (webpack-internal:///(sc_server)/./node_modules/langchain/dist/chains/question_answering/load.js:31:11)
    at makeChain (webpack-internal:///(sc_server)/./lib/makechain.ts:32:83)
    at POST (webpack-internal:///(sc_server)/./app/api/chat/route.tsx:40:80)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async eval (webpack-internal:///(sc_server)/./node_modules/next/dist/server/future/route-modules/app-route/module.js:265:37)

错误只发生在我通过的时候

{
      prompt: QA_PROMPT,
}

loadQAChain。
我的package.json看起来像这样：

{
  "private": true,
  "scripts": {
    "dev": "prisma generate && next dev",
    "server": "python manage.py runserver",
    "build": "prisma generate && prisma db push && next build",
    "start": "next start",
    "lint": "next lint",
    "ingest": "tsx -r dotenv/config scripts/ingest-data.ts"
  },
  "dependencies": {
    "@microsoft/fetch-event-source": "^2.0.1",
    "@pinecone-database/pinecone": "^0.1.6",
    "@prisma/client": "^4.14.0",
    "@radix-ui/react-accordion": "^1.1.2",
    "@types/node": "^18.11.9",
    "@types/react": "^18.0.25",
    "bcrypt": "^5.1.0",
    "clsx": "^1.2.1",
    "dotenv": "^16.3.1",
    "fs": "^0.0.1-security",
    "langchain": "^0.0.82",
    "lucide": "^0.246.0",
    "lucide-react": "^0.246.0",
    "next": "^13.4.2",
    "next-auth": "^4.22.1",
    "pdf-parse": "^1.1.1",
    "pinecone": "^0.1.0",
    "radix": "^0.0.0",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-hot-toast": "^2.4.1",
    "react-markdown": "^8.0.7",
    "sanitize-filename": "^1.6.3",
    "sanitize-html": "^2.10.0",
    "sass": "^1.63.4",
    "tailwind-merge": "^1.13.2"
  },
  "devDependencies": {
    "@types/bcrypt": "^5.0.0",
    "autoprefixer": "^10.4.4",
    "eslint": "8.11.0",
    "eslint-config-next": "^13.0.5",
    "postcss": "^8.4.12",
    "prisma": "^4.14.0",
    "tailwindcss": "^3.0.23",
    "typescript": "^4.6.2"
  }
}

我的tsconfig.json看起来像这样：

{
  "compilerOptions": {
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "baseUrl": ".",
    "paths": {
      "@/components/*": ["components/*"],
      "@/pages/*": ["pages/*"],
      "@/app/*": ["app/*"],
      "@/lib/*": ["lib/*"],
      "@/styles/*": ["styles/*"],
      "@/types/*": ["types/*"]
    },
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "noEmit": true,
    "esModuleInterop": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "preserve",
    "incremental": true,
    "plugins": [
      {
        "name": "next"
      }
    ]
  },
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
  "exclude": ["node_modules"]
}

我的OpenAI API Key和PineCone环境配置正确，我能够使用当前环境运行数据库摄取。有什么想法吗
我对langChain不是很熟悉，所以解释起来相当有挑战性。我试着使用不同的链条，但我不能让它们工作。我尝试删除模板，错误消失了，当然，这没有帮助。