diff --git a/pre_commit/languages/ruby.py b/pre_commit/languages/ruby.py
index 1a9b3fb3..ef649e73 100644
--- a/pre_commit/languages/ruby.py
+++ b/pre_commit/languages/ruby.py
@@ -3,7 +3,6 @@ from __future__ import annotations
 import contextlib
 import functools
 import importlib.resources
-import os
 import os.path
 import shutil
 import tarfile
@@ -46,7 +45,7 @@ def get_env_patch(
         ('GEM_HOME', os.path.join(venv, 'gems')),
         ('GEM_PATH', UNSET),
         ('BUNDLE_IGNORE_CONFIG', '1'),
-        ('BUNDLE_GEMFILE', os.path.join(venv, 'Gemfile'))
+        ('BUNDLE_GEMFILE', os.path.join(venv, 'Gemfile')),
     )
     if language_version == 'system':
         patches += (