python實踐：字符串大小寫轉換

#完成輸入字符串中的大小寫轉換
def ConverString(string):
    #string=str.swapcase(string)
    list=[]
    for i in string:
        if i.islower() is True:
            list.append(i.upper())
        elif i.isupper() is True:
            list.append(i.lower())
        else:
            list.append(i)
    print("".join(list))

if __name__=='__main__':
    string='adbc#$ABCD'
    ConverString(string)