Python 0x 处的函数> 输出

我写了一个新函数，当我执行它时，我得到一个错误:

<function read_grades at 0x000001F69E0FC8C8>

好的，这是我的代码:

def add(x, y): 
    z = x / y * 100 
    return z 
 
def calc_grade(perc): 
    if perc < 50: 
        return "1" 
    if perc <  60: 
        return "2" 
    if perc < 75: 
        return "3" 
    if perc < 90: 
        return "4" 
    if perc >= 90: 
        return "5" 
 
def calc_command(): 
    num1 = input("Input your points: ") 
    num2 = input("Input maximum points: ") 
    num3 = add(float(num1), float(num2)) 
    grade = calc_grade(num3) 
    print("This is your result:", str(num3) + "%") 
    print("Your grade:", grade) 
    save = open("grades.txt", "r") 
    read_grades = save.read() 
    save = open("grades.txt", "w") 
    save.write(read_grades + grade) 
    save.close() 
 
def read_grades(): 
    save = open("grades.txt", "r") 
    read_grades = save.read() 
    grades = read_grades.split() 
    save.close() 
    return grades 
 
while True: 
    command = input("Input your command: ") 
    if command == "CALC": 
        calc_command() 
    elif command == "EXIT": 
        break 
    elif command == "GRADES": 
        print(read_grades) 
    elif command == "HELP": 
        print("These are the commands:\nCALC - Calculates your grade and writes in the file.\nEXIT - Exits the program.\nGRADES - Reads your previous grades.\nHELP - This command. It helps you.") 
    else: 
        print("You inputed an invalid command. Type HELP for help.") 

当我执行 read_grades() 函数或 GRADES 命令时会发生此错误。

对于那些标记这个问题的人:我做了一些搜索，但没有找到那个帖子，现在我读了它，但我不明白答案