Added the method setCustomEmojiStickerSetThumbnail for editing the thumbnail of custom emoji sticker sets created by the bot.

telebot/__init__.py

@@ -4563,6 +4563,23 @@ class TeleBot:
         """
         result = apihelper.get_custom_emoji_stickers(self.token, custom_emoji_ids)
         return [types.Sticker.de_json(sticker) for sticker in result]
+    
+
+    def set_custom_emoji_sticker_set_thumbnail(self, name: str, custom_emoji_id: Optional[str]=None):
+        """
+        Use this method to set the thumbnail of a custom emoji sticker set.
+        Returns True on success.
+
+        :param name: Sticker set name
+        :type name: :obj:`str`
+
+        :param custom_emoji_id: Custom emoji identifier of a sticker from the sticker set; pass an empty string to drop the thumbnail and use the first sticker as the thumbnail.
+        :type custom_emoji_id: :obj:`str`
+
+        :return: Returns True on success.
+        :rtype: :obj:`bool`
+        """
+        return apihelper.set_custom_emoji_sticker_set_thumbnail(self.token, name, custom_emoji_id)
 
     def upload_sticker_file(self, user_id: int, png_sticker: Union[Any, str]=None, sticker: Optional[types.InputFile]=None, sticker_format: Optional[str]=None) -> types.File:
         """

telebot/apihelper.py

@@ -1628,6 +1628,13 @@ def upload_sticker_file(token, user_id, sticker, sticker_format):
     return _make_request(token, method_url, params=payload, files=files, method='post')
 
 
+def set_custom_emoji_sticker_set_thumbnail(token, name, custom_emoji_id=None):
+    method_url = 'setCustomEmojiStickerSetThumbnail'
+    payload = {'name': name}
+    if custom_emoji_id:
+        payload['custom_emoji_id'] = custom_emoji_id
+    return _make_request(token, method_url, params=payload, method='post')
+
 def create_new_sticker_set(
         token, user_id, name, title, stickers, sticker_format=None, sticker_type=None, needs_repainting=None):
     method_url = 'createNewStickerSet'

telebot/async_telebot.py

@@ -5458,6 +5458,22 @@ class AsyncTeleBot:
         
         result = await asyncio_helper.upload_sticker_file(self.token, user_id, sticker, sticker_format)
         return types.File.de_json(result)
+    
+    async def set_custom_emoji_sticker_set_thumbnail(self, name: str, custom_emoji_id: Optional[str]=None):
+        """
+        Use this method to set the thumbnail of a custom emoji sticker set.
+        Returns True on success.
+
+        :param name: Sticker set name
+        :type name: :obj:`str`
+
+        :param custom_emoji_id: Custom emoji identifier of a sticker from the sticker set; pass an empty string to drop the thumbnail and use the first sticker as the thumbnail.
+        :type custom_emoji_id: :obj:`str`
+
+        :return: Returns True on success.
+        :rtype: :obj:`bool`
+        """
+        return await asyncio_helper.set_custom_emoji_sticker_set_thumbnail(self.token, name, custom_emoji_id)
 
     async def create_new_sticker_set(
             self, user_id: int, name: str, title: str, 

telebot/asyncio_helper.py

@@ -1615,6 +1615,13 @@ async def upload_sticker_file(token, user_id, sticker, sticker_format):
     return await _process_request(token, method_url, params=payload, files=files, method='post')
 
 
+async def set_custom_emoji_sticker_set_thumbnail(token, name, custom_emoji_id=None):
+    method_url = 'setCustomEmojiStickerSetThumbnail'
+    payload = {'name': name}
+    if custom_emoji_id:
+        payload['custom_emoji_id'] = custom_emoji_id
+    return await _process_request(token, method_url, params=payload, method='post')
+
 async def create_new_sticker_set(
         token, user_id, name, title, stickers, sticker_format=None, sticker_type=None, needs_repainting=None):
     method_url = 'createNewStickerSet'