优化代码，提高解耦

04_langchain_basics/03_chain.py

@@ -1,10 +1,4 @@
-import os
-from dotenv import load_dotenv
-
-load_dotenv()
-api_key = os.getenv("OPENAI_API_KEY")
-
-
+from config import OPENAI_API_KEY
 from langchain_core.prompts import ChatPromptTemplate
 from langchain_openai import ChatOpenAI
 from langchain_core.output_parsers import StrOutputParser
@@ -18,7 +12,7 @@ prompt = ChatPromptTemplate.from_messages([
 # 初始化模型
 llm = ChatOpenAI(
     model="deepseek-chat",
-    api_key=api_key,
+    api_key=OPENAI_API_KEY,
     base_url="https://api.deepseek.com"
 )