diff --git a/content/Building Systems with the ChatGPT API/3.Classification.ipynb b/content/Building Systems with the ChatGPT API/3.Classification.ipynb
index 5198713..181fddd 100644
--- a/content/Building Systems with the ChatGPT API/3.Classification.ipynb	
+++ b/content/Building Systems with the ChatGPT API/3.Classification.ipynb	
@@ -30,7 +30,7 @@
     "import openai\n",
     "from dotenv import load_dotenv, find_dotenv\n",
     "_ = load_dotenv(find_dotenv()) # read local .env file\n",
-    "os.environ['OPENAI_API_KEY']"
+    "openai.api_key = os.environ['OPENAI_API_KEY']"
    ]
   },
   {