diff --git a/pre_commit_hooks/check_dco.py b/pre_commit_hooks/check_dco.py
index e3f86c8..1e3a5b2 100644
--- a/pre_commit_hooks/check_dco.py
+++ b/pre_commit_hooks/check_dco.py
@@ -7,7 +7,6 @@ in commit-msg stage) and checks that it contains a valid
 This is a pure Python implementation with no external dependencies —
 only the standard library is used (``re``, ``sys``).
 """
-
 from __future__ import annotations
 
 import argparse
@@ -32,7 +31,7 @@ def check_dco(commit_msg_path: str) -> tuple[int, list[str]]:
 
     Returns (exit_code, diagnostic_messages).
     """
-    with open(commit_msg_path, 'r', encoding='utf-8') as f:
+    with open(commit_msg_path, encoding='utf-8') as f:
         lines = f.read().splitlines()
 
     errors: list[str] = []
diff --git a/tests/check_dco_test.py b/tests/check_dco_test.py
index d749345..73d856f 100644
--- a/tests/check_dco_test.py
+++ b/tests/check_dco_test.py
@@ -1,10 +1,12 @@
 from __future__ import annotations
 
 import os
-import pytest
 import tempfile
 
-from pre_commit_hooks.check_dco import check_dco, main
+import pytest
+
+from pre_commit_hooks.check_dco import check_dco
+from pre_commit_hooks.check_dco import main
 
 
 def _write_commit_msg(content: str) -> str: