style: some of the suggestions from flake8
diff --git a/serial/urlhandler/protocol_loop.py b/serial/urlhandler/protocol_loop.py
index fdd4f9c..7415128 100644
--- a/serial/urlhandler/protocol_loop.py
+++ b/serial/urlhandler/protocol_loop.py
@@ -25,7 +25,7 @@
 except ImportError:
     import Queue as queue
 
-from serial.serialutil import *
+from serial.serialutil import SerialBase, SerialException, to_bytes, iterbytes, writeTimeoutError
 
 # map log level names to constants. used in from_url()
 LOGGER_LEVELS = {