Update app.py

app.py

@@ -172,7 +172,7 @@ def format_part(current_text: str, previous_text: str, finish_reason: str):
             'index': 0,
             'delta': {'content': current_text[len(previous_text):]},
             'finish_reason': finish_reason
-        }]}, ensure_ascii=False)}\n\n"
+        }]}, ensure_ascii=False)}\n\n".encode('utf-8')
 
 
 async def fetch_reka_stream(data: dict) -> AsyncGenerator[str, None]: