我刚开始使用python，自从我开始了一个新的计算器项目以来，pyCharm一无所获。我不确定导致此错误的原因，如果能在这里获得帮助，我将不胜感激。（这只是我要显示的主要功能）这是代码：

def main():
    run = True
    while run == True:
        if run == False:
        break
    try:
        operation = input(print("Would you like to *, -, + or /?"))

        if operation != "+" and operation != "-" and operation != "/" and operation != "*":
            print("invalid input.")
            go = input(print("Would you like to continue, yes or no?"))

        if go == "no":
            run = False

        else:
            continue

        else:
            num1 = int(input(print("What's your first number?")))

            num2 = int(input(print("What's your second number?")))

         if operation == "*":
            print(multi(num1, num2))

         if operation == "-":
            print(sub(num1, num2))

         if operation == "+":
               print(add(num1, num2))

         if operation == "/":
               print(div(num1, num2))

         go = input(print("Would you like to make another calculation, yes or no?"))
         if go == "no":
                run = False
                else:
                    continue

        except:
            print("invalid input.")
            go = input(print("Would you like to continue, yes or no?"))
            if go == "no":
                run = False
            else:
               continue

发生的情况的一个示例：

Would you like to *, -, + or /?
None/
What's your first number?
None3
What's your second number?
None4
0.75
Would you like to make another calculation, yes or no?
Noneno

Process finished with exit code 0