Update type annotations

1 files changed, 3 insertions, 3 deletions

diff --git a/sphinx/util/i18n.py b/sphinx/util/i18n.py
index 3a5aca58e..d647d6d05 100644
--- a/sphinx/util/i18n.py
+++ b/sphinx/util/i18n.py
@@ -12,7 +12,7 @@ import os
 import re
 from datetime import datetime, timezone
 from os import path
-from typing import TYPE_CHECKING, Callable, Generator, List, NamedTuple, Tuple, Union
+from typing import TYPE_CHECKING, Callable, Generator, List, NamedTuple, Optional, Tuple, Union
 
 import babel.dates
 from babel.messages.mofile import write_mo
@@ -170,7 +170,7 @@ date_format_mappings = {
 date_format_re = re.compile('(%s)' % '|'.join(date_format_mappings))
 
 
-def babel_format_date(date: datetime, format: str, locale: str,
+def babel_format_date(date: datetime, format: str, locale: Optional[str],
                       formatter: Callable = babel.dates.format_date) -> str:
     if locale is None:
         locale = 'en'
@@ -191,7 +191,7 @@ def babel_format_date(date: datetime, format: str, locale: str,
         return format
 
 
-def format_date(format: str, date: datetime = None, language: str = None) -> str:
+def format_date(format: str, date: datetime = None, language: Optional[str] = None) -> str:
     if date is None:
         # If time is not specified, try to use $SOURCE_DATE_EPOCH variable
         # See https://wiki.debian.org/ReproducibleBuilds/TimestampsProposal