try fix error

app.py

@@ -64,8 +64,9 @@ def generate(text, file_name, model="gemini-2.0-flash-exp"):
                 continue
             candidate = chunk.candidates[0].content.parts[0]
 
-            text_response += chunk.text + "\n"
-
+            text_part = getattr(candidate, "text", "")
+            if text_part:
+                text_response += text_part + "\n"
 
             if candidate.inline_data:
                 save_binary_file(temp_path, candidate.inline_data.data)