Use asottile/add-trailing-comma
diff --git a/tests/check_merge_conflict_test.py b/tests/check_merge_conflict_test.py
index 5a2e82a..a999aca 100644
--- a/tests/check_merge_conflict_test.py
+++ b/tests/check_merge_conflict_test.py
@@ -45,7 +45,7 @@
             'child\n'
             '=======\n'
             'parent\n'
-            '>>>>>>>'
+            '>>>>>>>',
         ) or f1.startswith(
             '<<<<<<< HEAD\n'
             'child\n'
@@ -53,7 +53,7 @@
             '||||||| merged common ancestors\n'
             '=======\n'
             'parent\n'
-            '>>>>>>>'
+            '>>>>>>>',
         ) or f1.startswith(
             # .gitconfig with [pull] rebase = preserve causes a rebase which
             # flips parent / child
@@ -61,7 +61,7 @@
             'parent\n'
             '=======\n'
             'child\n'
-            '>>>>>>>'
+            '>>>>>>>',
         )
         assert os.path.exists(os.path.join('.git', 'MERGE_MSG'))
         yield