Update app.py

app.py

@@ -129,12 +129,10 @@ def index_from_url(url: str) -> Tuple[str, str]:
 
 def query_gpt(query: str, retrieved_images: list[tuple[Image.Image, str]]) -> str:
     """Calls OpenAI's GPT model with the query and image data."""
-    if api_key and api_key.startswith("sk"):
+    if api_key_env and api_key_env.startswith("sk"):
         try:
-            from openai import OpenAI
-
             base64_images = [encode_image_to_base64(im_caption[0]) for im_caption in retrieved_images]
-            client = OpenAI(api_key=api_key.strip())
+            client = OpenAI(api_key=api_key_env)
             PROMPT = """
 You are a smart assistant designed to answer questions about a PDF document.
 You are given relevant information in the form of PDF pages. Use them to construct a short response to the question, and cite your sources (page numbers, etc).