chore: fix flake8 issue

Author: theskumar

setup.cfg

@@ -7,7 +7,7 @@ tag = True
 
 [flake8]
 max-line-length = 120
-exclude = .tox,.git,docs,venv,.venv
+exclude = .tox,.git,docs,venv,.venv,build
 
 [mypy]
 check_untyped_defs = true

tests/test_main.py

@@ -24,7 +24,7 @@ def test_set_key_no_file(tmp_path):
 
 def test_set_key_invalid_file():
     with pytest.raises(TypeError):
-        result = dotenv.set_key(None, "foo", "bar")
+        dotenv.set_key(None, "foo", "bar")
 
 
 @pytest.mark.parametrize(