app parse diff message

app/demo.py

@@ -42,7 +42,7 @@ def do_p2_im_message_receive_v1(data: P2ImMessageReceiveV1) -> None:
 
         for item in chain.from_iterable(content):
             if item.get("tag") == "text":
-                content = message_content += item["text"]
+                message_content += item["text"]
                 break
             elif item.get("tag") == "img":
                 images.append(item["image_key"])