Update app.py

app.py

@@ -6,7 +6,12 @@ from langchain.llms import OpenAI
 from langchain.prompts import ChatPromptTemplate
 
 # Set up environment variable for OpenAI API key
-os.environ["OPENAI_API_KEY"] = os.getenv("k1")
+api_key = os.getenv("k1")
+
+if api_key is None:
+    st.error("API key not found. Please set the 'k1' environment variable.")
+else:
+    os.environ["OPENAI_API_KEY"] = api_key
 
 # Initialize OpenAI with LangChain
 llm = OpenAI(api_key=os.environ["OPENAI_API_KEY"], model="gpt-3.5-turbo", temperature=0)