diff --git a/cibuildwheel/macos.py b/cibuildwheel/macos.py
index 839e2508..71eea5e7 100644
--- a/cibuildwheel/macos.py
+++ b/cibuildwheel/macos.py
@@ -285,7 +285,9 @@ def build(options: Options, tmp_path: Path) -> None:
                 env = before_all_options.environment.as_dictionary(prev_environment=os.environ)
                 env.setdefault("MACOSX_DEPLOYMENT_TARGET", "10.9")
                 before_all_prepared = prepare_command(
-                    before_all_options.before_all, project=".", package=before_all_options.package_dir
+                    before_all_options.before_all,
+                    project=".",
+                    package=before_all_options.package_dir,
                 )
                 shell(before_all_prepared, env=env)