public static StaticArena3x3ShopItemData AssertItemIsNotPurchased(this StaticArena3x3ShopItemData item, UserArena3x3ShopItemData boughtItem) => default;
public static StaticArena3x3ShopItemData AssertIsAvailable(this StaticArena3x3ShopItemData item, ArenaLeagueId leagueId) => default;
public static StaticArena3x3ShopItemData AssertCooldownPassed(this StaticArena3x3ShopItemData item, UserArena3x3ShopItemData boughtItem) => default;
private static bool AllYearOrCurrentMonthItem(StaticArena3x3ShopItemData shopItem) => default;