Update app.py

app.py

@@ -95,6 +95,7 @@ def extract_pdf_md(pdf_dir):
     return content
 
 
+
 def openai_api(messages, model="claude-sonnet-4-5-20250929", temperature=0.1):
     print("use model:", model, "temperature:", temperature)
     try:
@@ -105,8 +106,12 @@ def openai_api(messages, model="claude-sonnet-4-5-20250929", temperature=0.1):
             max_tokens=8192,
             stream=True
         )
-        response = ''.join(
-            [chunk.choices[0].delta.content if chunk.choices[0].delta.content else "" for chunk in completion])
+        response = ""
+        for chunk in completion:
+            if chunk.choices and len(chunk.choices) > 0:
+                delta = chunk.choices[0].delta
+                if delta.content:
+                    response += delta.content
         return response
     except Exception as ex:
         print("API error:", ex)