我是 python 新手，這是我的代碼，.lower 通常可以工作，但這次不行。technical_dict = {        dict : 'stores a key/value pair',        list : 'stores a value at each index',        map : 'see dict',        set : 'stores unordered unique elements'    }    userInput = (input("What term would you like to lookup or type 'exit' to stop:"))    if userInput.lower() not in technical_dict:        print("Term does not exist in technical dictionary")    if userInput.lower()  in technical_dict:        print(technical_dict[userInput.lower()])        while userInput.lower() != "exit":            userInput = input("What term would you like to lookup or type 'exit' to stop:")            if userInput.lower() in technical_dict:        print(technical_dict[userInput.lower()])            if userInput.lower() not in technical_dict:                print("Term does not exist in technical dictionary")                break