Fix linting errors

Also tweaked the makefile rules so that `make test` will always lint first. I usually test before pushing
but forget to lint, so this should keep me honest

Author: Crozzers

.github/workflows/tests.yaml

@@ -39,7 +39,7 @@ jobs:
           python -m pip install -r requirements-dev.txt
       - name: Lint with flake8
         run: |
-          flake8 screen_brightness_control --max-line-length=119 --ignore=W503
+          make lint
       - name: Run tests
         run: |
-          python tests/testall.py --synthetic
+          make test

Makefile

@@ -1,9 +1,17 @@
 SHELL=/bin/bash
 
-.PHONY: test
-test:
+.PHONY: lint
+lint:
+	python -m flake8 screen_brightness_control --max-line-length 119 --ignore W503
+
+.PHONY: testquick
+testquick:
 	python tests/testall.py --synthetic
 
+.PHONY: test
+test: lint
+	make testquick
+
 .PHONY: testall
 testall:
 	python tests/testall.py

screen_brightness_control/helpers.py

@@ -4,7 +4,6 @@
 from __future__ import annotations
 
 import logging
-import platform
 import struct
 import subprocess
 import time