/**
 * @typedef {Object} FriendWeekData
 *
 * @property {number} id
 * The id of the friend.
 *
 * @property {string} username
 * The username of the friend.
 *
 * @property {number[]} prices
 * A list of prices for each slot.
 * null values can be used for missing prices.
 *
 * @property {AdviceData} advice
 * Advice for the friend.
 */