python: update README.md

python/README.md

@@ -12,18 +12,25 @@ pip install .
 ### Stream
 
 ```python
+from loguru import logger
+
 from bbgo import Stream
-from bbgo import bbgo_pb2
-
-subscriptions = [
-    bbgo_pb2.Subscription(exchange='max', channel=bbgo_pb2.Channel.BOOK, symbol='btcusdt', depth=2),
-    bbgo_pb2.Subscription(exchange='max', channel=bbgo_pb2.Channel.BOOK, symbol='ethusdt', depth=2),
-    ...
-]
-
-stream = Stream(host, port, subscriptions)
-stream.on_book_event(book_event_callback)
-stream.on_ticker_event(ticker_event_callback)
-...
+from bbgo.data import Event
+from bbgo.handlers import UpdateHandler
+
+
+class LogBook(UpdateHandler):
+
+    def handle(self, event: Event) -> None:
+        logger.info(event)
+
+
+host = '127.0.0.1'
+port = 50051
+
+stream = Stream(host, port)
+stream.subscribe('max', 'book', 'BTCUSDT', 'full')
+stream.subscribe('max', 'book', 'ETHUSDT', 'full')
+stream.add_event_handler(LogBook())
 stream.start()
 ```