diff --git a/src/_pytest/config/__init__.py b/src/_pytest/config/__init__.py
index d0f0402ba..d753a9054 100644
--- a/src/_pytest/config/__init__.py
+++ b/src/_pytest/config/__init__.py
@@ -837,7 +837,7 @@ def _iter_rewritable_modules(package_files: Iterable[str]) -> Iterator[str]:
             module_name, _ = os.path.splitext(fn)
             # we ignore "setup.py" at the root of the distribution
             # as well as editable installation finder modules made by setuptools
-            if module_name != "setup" and not module_name.startswith('__editable__'):
+            if module_name != "setup" and not module_name.startswith("__editable__"):
                 seen_some = True
                 yield module_name
         elif is_package: