diff --git a/src/black/comments.py b/src/black/comments.py
index eb53ff8..7cf15bf 100644
--- a/src/black/comments.py
+++ b/src/black/comments.py
@@ -238,9 +238,7 @@ def generate_ignored_nodes(leaf: Leaf, comment: ProtoComment) -> Iterator[LN]:
                 if (
                     child.type == token.INDENT
                     and index < len(container.children) - 1
-                    and children_contains_fmt_on(
-                        container.children[index + 1]
-                    )
+                    and children_contains_fmt_on(container.children[index + 1])
                 ):
                     # This means `# fmt: on` is placed right after an indentation
                     # level, and we shouldn't swallow the previous INDENT token.
diff --git a/src/black/mode.py b/src/black/mode.py
index 163a42d..0645440 100644
--- a/src/black/mode.py
+++ b/src/black/mode.py
@@ -154,7 +154,6 @@ class Preview(Enum):
     # NOTE: string_processing requires wrap_long_dict_values_in_parens
     # for https://github.com/psf/black/issues/3117 to be fixed.
     string_processing = auto()
-    skip_magic_trailing_comma_in_subscript = auto()
     wrap_long_dict_values_in_parens = auto()