diff --git a/cibuildwheel/windows.py b/cibuildwheel/windows.py
index 73691d8f..98132689 100644
--- a/cibuildwheel/windows.py
+++ b/cibuildwheel/windows.py
@@ -95,7 +95,7 @@ def install_cpython(version: str, arch: str, nuget: Path) -> Path:
 
 
 def install_pypy(version: str, arch: str, url: str) -> Path:
-    assert arch == '64' and 'win64' in url
+    assert arch == "64" and "win64" in url
     # Inside the PyPy zip file is a directory with the same name
     zip_filename = url.rsplit("/", 1)[-1]
     extension = ".zip"
diff --git a/test/utils.py b/test/utils.py
index 61c9ea10..d5f87b02 100644
--- a/test/utils.py
+++ b/test/utils.py
@@ -157,7 +157,7 @@ def expected_wheels(
             if python_abi_tag.startswith("cp"):
                 platform_tags = ["win32", "win_amd64"]
             else:
-                platform_tags = ['win_amd64']
+                platform_tags = ["win_amd64"]
 
         elif platform == "macos":
             if python_abi_tag == "cp39-cp39" and machine_arch == "arm64":
diff --git a/unit_test/build_selector_test.py b/unit_test/build_selector_test.py
index c57bb146..670fe60a 100644
--- a/unit_test/build_selector_test.py
+++ b/unit_test/build_selector_test.py
@@ -92,7 +92,7 @@ def test_build_limited_python():
     assert not build_selector("cp36-win32")
     assert build_selector("cp37-win32")
     assert build_selector("cp38-win32")
-    assert build_selector('pp37-win_amd64')
+    assert build_selector("pp37-win_amd64")
 
 
 def test_build_limited_python_partial():