How many followers does the list created by the user whose user_avatar_image_url is https://assets.mubicdn.net/images/avatars/74983/images-w150.jpg?1523895214 have?
followers refers to list_followers;
SELECT SUM(T2.list_followers) FROM lists_users AS T1 INNER JOIN lists AS T2 ON T1.list_id = T2.list_id WHERE T1.user_avatar_image_url = 'https://assets.mubicdn.net/images/avatars/74983/images-w150.jpg?1523895214'