diff --git a/stream_chat/async_chat/channel.py b/stream_chat/async_chat/channel.py
index a66fb7f..458417d 100644
--- a/stream_chat/async_chat/channel.py
+++ b/stream_chat/async_chat/channel.py
@@ -195,7 +195,9 @@ async def hide(self, user_id: str) -> StreamResponse:
     async def show(self, user_id: str) -> StreamResponse:
         return await self.client.post(f"{self.url}/show", data={"user_id": user_id})
 
-    async def mute(self, user_id: str, expiration: int = None) -> StreamResponse:
+    async def mute(
+        self, user_id: str, expiration: Optional[int] = None
+    ) -> StreamResponse:
         params: Dict[str, Union[str, int]] = {
             "user_id": user_id,
             "channel_cid": self.cid,
diff --git a/stream_chat/async_chat/client.py b/stream_chat/async_chat/client.py
index ce07f6d..1f315b0 100644
--- a/stream_chat/async_chat/client.py
+++ b/stream_chat/async_chat/client.py
@@ -325,7 +325,7 @@ async def translate_message(self, message_id: str, language: str) -> StreamRespo
         )
 
     async def pin_message(
-        self, message_id: str, user_id: str, expiration: int = None
+        self, message_id: str, user_id: str, expiration: Optional[int] = None
     ) -> StreamResponse:
         updates = {
             "set": {
diff --git a/stream_chat/base/channel.py b/stream_chat/base/channel.py
index 8e300a5..feb8ac3 100644
--- a/stream_chat/base/channel.py
+++ b/stream_chat/base/channel.py
@@ -420,7 +420,7 @@ def show(self, user_id: str) -> Union[StreamResponse, Awaitable[StreamResponse]]
 
     @abc.abstractmethod
     def mute(
-        self, user_id: str, expiration: int = None
+        self, user_id: str, expiration: Optional[int] = None
     ) -> Union[StreamResponse, Awaitable[StreamResponse]]:
         """
         Mutes a channel.
diff --git a/stream_chat/base/client.py b/stream_chat/base/client.py
index c6f2d94..ed3628a 100644
--- a/stream_chat/base/client.py
+++ b/stream_chat/base/client.py
@@ -513,7 +513,7 @@ def translate_message(
 
     @abc.abstractmethod
     def pin_message(
-        self, message_id: str, user_id: str, expiration: int = None
+        self, message_id: str, user_id: str, expiration: Optional[int] = None
     ) -> Union[StreamResponse, Awaitable[StreamResponse]]:
         """
         Pins a message.
diff --git a/stream_chat/channel.py b/stream_chat/channel.py
index 2373811..0c1c813 100644
--- a/stream_chat/channel.py
+++ b/stream_chat/channel.py
@@ -196,7 +196,7 @@ def hide(self, user_id: str) -> StreamResponse:
     def show(self, user_id: str) -> StreamResponse:
         return self.client.post(f"{self.url}/show", data={"user_id": user_id})
 
-    def mute(self, user_id: str, expiration: int = None) -> StreamResponse:
+    def mute(self, user_id: str, expiration: Optional[int] = None) -> StreamResponse:
         params: Dict[str, Union[str, int]] = {
             "user_id": user_id,
             "channel_cid": self.cid,
diff --git a/stream_chat/client.py b/stream_chat/client.py
index b9572b1..2d5c98f 100644
--- a/stream_chat/client.py
+++ b/stream_chat/client.py
@@ -318,7 +318,7 @@ def commit_message(self, message_id: str) -> StreamResponse:
         return self.post(f"messages/{message_id}/commit")
 
     def pin_message(
-        self, message_id: str, user_id: str, expiration: int = None
+        self, message_id: str, user_id: str, expiration: Optional[int] = None
     ) -> StreamResponse:
         updates = {
             "set": {