style: more on imports (flake8 warnings)
diff --git a/serial/urlhandler/protocol_loop.py b/serial/urlhandler/protocol_loop.py
index 7415128..51217d5 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 SerialBase, SerialException, to_bytes, iterbytes, writeTimeoutError
+from serial.serialutil import SerialBase, SerialException, to_bytes, iterbytes, writeTimeoutError, portNotOpenError
# map log level names to constants. used in from_url()
LOGGER_LEVELS = {