diff --git a/redbot/cogs/mutes/mutes.py b/redbot/cogs/mutes/mutes.py
index 4909cd16358..49674c4df3b 100644
--- a/redbot/cogs/mutes/mutes.py
+++ b/redbot/cogs/mutes/mutes.py
@@ -1750,7 +1750,7 @@ async def mute_user(
     async def unmute_user(
         self,
         guild: discord.Guild,
-        author: Union[discord.Member, None],
+        author: Optional[discord.Member],
         user: discord.Member,
         reason: Optional[str] = None,
     ) -> MuteResponse: