I am pretty sure the id of my list is right.

Requestment information:

• json: {'items': [{'media_type': 'movie', 'media_id': 156022}]}
• method: POST
• headers: {'accept': 'application/json', 'Authorization': 'Bearer xxx', 'content-type': 'application/json'}
• url: https://api.themoviedb.org/4/8272324/items (the list is private)