diff --git a/pi_mqtt_gpio/server.py b/pi_mqtt_gpio/server.py
index c448af36d7219ce831f1ac47af1cf935cad331f5..e43164de33bcdc64704da3e0f4381bca370f652b 100644
--- a/pi_mqtt_gpio/server.py
+++ b/pi_mqtt_gpio/server.py
@@ -2,26 +2,24 @@ import argparse
 import json
 import logging
 import logging.config
-import yaml
-import sys
 import socket
 import ssl
-from time import sleep, time
-from importlib import import_module
-from hashlib import sha1
-
-import threading  # For callback functions
-from fractions import gcd  # for calculating the callback periodic time
+import sys
+import threading
 from functools import reduce
+from hashlib import sha1
+from importlib import import_module
+from math import gcd
+from time import sleep, time
 
-import paho.mqtt.client as mqtt
 import cerberus
+import paho.mqtt.client as mqtt
+import yaml
 
 from pi_mqtt_gpio import CONFIG_SCHEMA
-from pi_mqtt_gpio.modules import PinPullup, PinDirection, InterruptEdge, BASE_SCHEMA
+from pi_mqtt_gpio.modules import BASE_SCHEMA, InterruptEdge, PinDirection, PinPullup
 from pi_mqtt_gpio.scheduler import Scheduler, Task
 
-
 LOG_LEVEL_MAP = {
     mqtt.MQTT_LOG_INFO: logging.INFO,
     mqtt.MQTT_LOG_NOTICE: logging.INFO,
@@ -317,7 +315,7 @@ def install_missing_requirements(module):
         if pkgs_installed.find(pkg_resources.Requirement.parse(req)) is None:
             pkgs_required.append(req)
     if pkgs_required:
-        from subprocess import check_call, CalledProcessError
+        from subprocess import CalledProcessError, check_call
 
         try:
             check_call([sys.executable, "-m", "pip", "install"] + pkgs_required)