➕ Add isort and ruff as dev dependencies;

➖ remove `flake8` dependency (replaced by `ruff`);
change `lint.sh` script to use `isort`, `ruff`, and `black`

tests/__main__.py

@@ -1,7 +1,6 @@
 import sys
 import unittest
 
-
 if __name__ == "__main__":
     try:
         pattern = sys.argv[1]

tests/test__util.py

@@ -12,9 +12,7 @@ class GenericInsightMixinTestCase(TestCase):
         mock_super.return_value = MagicMock(__init_subclass__=mock_super_meth)
 
         # Should be `None` by default:
-        self.assertIsNone(
-            _util.GenericInsightMixin._type_arg  # type: ignore[misc]
-        )
+        self.assertIsNone(_util.GenericInsightMixin._type_arg)  # type: ignore[misc]
 
         # If the mixin type argument was not specified (still generic),
         # ensure that the attribute remains `None` on the subclass: