Python 基本计算器，多种输入和选择通过功能

从我的代码可以看出，我想做一个基本的计算器，你先被问到你想做什么，然后被要求输入两个数字，由代码算出。我遇到了一个问题，代码没有返回任何内容，甚至没有尝试使用它要使用的函数

##Simple Calculator program##
print("Welcome to my basic calculator program")

print("In this program you will be asked to input what function you want to do then")
print("select 2 numbers, where the program will then do the mathematic operation on those 2 numbers")
#Class containing the functions and basic caluclation
 
class calculator_class():
    print("Please select a function by entering these :")
    print("Addition")
    print("Subtraction")
    print("Multiplication")
    print("Division")
    #this is a function which asks the user to choose what operator to choose before choosing their number
    
    def userchoice():
        
        userchoices = str(input())
        if userchoices in ["Addition","Subtraction","Multiplication","Division"]:
            return(
        
        
        if userchoices == "Addition":
            print(addition())
        elif userchoices == "Subtraction":
            print(subtraction())
        elif userchoices == "multiplication":
            print(multiplication())
        elif userchoices == "division":
            print(division())
        else:
            print(invalid_choice())
    print(userchoice())
    #here the user chooses the 2 numbers
    print("Please select 2 numbers to calculate")
        
    usernumber1 = int(input("Please input your first number here  : "))
    usernumber2 = int(input("Please input your second number here : "))
        
    #Functions of which contain addition, subtraction, multiplication and division
    def addition():
        print("A D D I T I O N")
        print("Just calculating...")
        
        print(usernumber1 + usernumber2)
        
    
    def subtraction():
        print("S U B T R A C T I O N")
        print("Just calculating...")
        print(usernumber1 - usernumber2)
        
    
    def multipliction():
        print("M U L T I P L I C A T I O N ")
        print("Just calculating...")
        print(usernumber1 * usernumber2)
        
    
    def division():
        print("D I V I S I O N ")
        print("Just calculatin...")
        print(usernumber1 / usernumber2)
        
        
    def invalid_choice():
        print("You did not pick a valid option, please try again")
    

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在这段代码中有很多错误的方法

只键入一个符号（*例如）比键入“乘法”更容易

最好对每个用户输入应用

.lower（）

python中的输入总是str，因此

userchoices=str（input（））

中的

str（）

是多余的

int（）