diff --git a/serial/tools/list_ports_osx.py b/serial/tools/list_ports_osx.py
index 4f3b9c5..17883fd 100644
--- a/serial/tools/list_ports_osx.py
+++ b/serial/tools/list_ports_osx.py
@@ -22,7 +22,6 @@
 # Also see the 'IORegistryExplorer' for an idea of what we are actually searching
 
 import ctypes
-from ctypes import util
 
 from serial.tools import list_ports_common
 
diff --git a/serial/urlhandler/protocol_alt.py b/serial/urlhandler/protocol_alt.py
index 6c81813..af1646a 100644
--- a/serial/urlhandler/protocol_alt.py
+++ b/serial/urlhandler/protocol_alt.py
@@ -16,9 +16,6 @@
 #   use poll based implementation on Posix (Linux):
 #   python -m serial.tools.miniterm alt:///dev/ttyUSB0?class=PosixPollSerial
 
-import sys
-import time
-
 import serial
 
 try:
@@ -50,5 +47,5 @@
 
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 if __name__ == '__main__':
-    s = serial_for_url('alt:///dev/ttyS0?class=PosixPollSerial')
+    s = serial.serial_for_url('alt:///dev/ttyS0?class=PosixPollSerial')
     print(s)
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 = {
diff --git a/serial/urlhandler/protocol_rfc2217.py b/serial/urlhandler/protocol_rfc2217.py
index 1357173..c14c792 100644
--- a/serial/urlhandler/protocol_rfc2217.py
+++ b/serial/urlhandler/protocol_rfc2217.py
@@ -7,4 +7,4 @@
 #
 # SPDX-License-Identifier:    BSD-3-Clause
 
-from serial.rfc2217 import Serial
+from serial.rfc2217 import Serial # noqa
diff --git a/serial/urlhandler/protocol_socket.py b/serial/urlhandler/protocol_socket.py
index 7932ee0..2f01a4a 100644
--- a/serial/urlhandler/protocol_socket.py
+++ b/serial/urlhandler/protocol_socket.py
@@ -16,6 +16,7 @@
 # options:
 # - "debug" print diagnostic messages
 
+import errno
 import logging
 import select
 import socket