Update retriever.py

retriever.py

@@ -1,9 +1,10 @@
 from PyPDF2 import PdfReader
 from google import genai
 import time
+import os
 
 # set up authentication
-api_key = userdata.get("GEMINI_API_KEY")
+api_key = os.getenv("GEMINI_API_KEY")
 client = genai.Client(api_key=api_key)
 
 # read in documents