我正在嘗試編寫一個(gè)搜索數(shù)據(jù)對(duì)象列表的代碼，如果用戶沒(méi)有輸入?yún)⒖继?hào)，當(dāng)用戶輸入有效的參考號(hào)時(shí)，它應(yīng)該打印“沒(méi)有找到這樣的項(xiàng)目”，它應(yīng)該顯示有關(guān)該項(xiàng)目的信息. 我的代碼現(xiàn)在的方式是，它不會(huì)為每個(gè)數(shù)據(jù)對(duì)象打印沒(méi)有這樣的項(xiàng)目，而不僅僅是一次。我怎樣才能讓它只打印一次？def initialize():    medialist=[    MediaItem("TU2RL012","Movie","2001: A Space Odyssey",11.99, None ,"Stanley Kubrick","Keir Dullea"),    MediaItem("GV5N32M9","Book","A Brief History of Time",10.17,"Stephen Hawking", None, None),    MediaItem("1DB6HK3L","Movie","North by Northwest",8.99, None, "Alfred Hitchcock","Cary Grant"),    MediaItem("PO5T7Y89","Movie", "The Good, The Bad, The Ugly",9.99,None,"Sergio Leone", "Clint Eastwood"),    MediaItem("TR3FL0EW","Book","The Alchemist",6.99,"Paulo Coelho", None,None),    MediaItem("F2O9PIE9", "Book", "Thus Spoke Zarathustra",7.81, "Friedrich Nietzsche", None, None),    MediaItem("R399CED1","Book", "Jonathan Living Seagull",6.97,"Richard Bach", None, None),    MediaItem("2FG6B2N9","Movie", "Gone with the Wind",4.99, "Victor Fleming","Vivien Leigh", None),    MediaItem("6Y9OPL87","Book", "Gone with the Wind",7.99, "Margarett Mitchell", None, None)]    return medialistdef search_item():    referencenum=input("Enter item reference:")    for obj in initialize():        if referencenum != obj.reference:            print("No Such Object found")`