I was asked to write a calculator in Python, and I completed it, but there is only one issue that needs to be fixed.

What is the prerequisite? "Once the user inputs/selects an arithmetic operation, the program should ask the user to enter the two operands one by one, separated by Enter key. If the user made a mistake while entering the parameters, he can return to main menu by pressing ‘$’ key at the end of the input string, followed by the Enter key.

I'll give you the code I wrote here, and I'd appreciate it if you could make this to get the return function.

def Add(a, b):return a + b# Function to subtract two numbers 
def Subtract(a, b):return a - b# Function to multiply two numbers
def Multiply(a, b):return a * b# Function to divide two numbers
def Divide(a, b):return a / b# Function to power two numbers
def Power(a, b):return a ** b# Function to remaind two numbers
def Remainder(a, b):return a % bdef Reset(a,b):return print(choice)while True:print("Select operation.")print("1.Add      : + ")print("2.Subtract : - ")print("3.Multiply : * ")print("4.Divide   : / ")print("5.Power    : ^ ")print("6.Remainder: % ")print("7.Terminate: # ")print("8.Reset    : $ ")# take input from the userchoice = input("Enter choice(+,-,*,/,^,%,#,$): ")print(choice)if choice in ('+', '-', '*', '/', '^', '%', '#', '$'):if choice == '#':print("Done. Terminating")breaka = input('Enter first number: ')print(str(a))b = input('Enter second number: ')print(str(b))if choice == '+':print(float(a), "+" ,float(b), "=", Add(float(a), float(b)))elif choice == '-':print(float(a), "-",float(b), "=", Subtract(float(a), float(b)))elif choice == '*':print(float(a), "*",float(b), "=", Multiply(float(a), float(b)))elif choice == '/':if int(b) != 0:print(float(a), "/", float(b), "=", Divide(float(a), float(b)))breakelse:print("float division by zero")print(float(a), "/", float(b), "=", "None")elif choice == '^':print(float(a), "**",float(b), "=", Power(float(a), float(b)))elif choice == '%':print(float(a), "%",float(b), "=", Remainder(float(a), float(b)))breakelse:print('Not a valid number,please enter again.')```

This kind of task is best (IMHO) handled in a so-called "table driven" manner. In other words, you create a table (in this case a dictionary) that has all the options built into it. Your core code then becomes much easier and the functionality is more extensible because all you need to do is add to or take away from the dictionary.

This structure also demonstrates how the user can be prompted for more input if/when something goes wrong.

def Add(a, b):return a + bdef Subtract(a, b):return a - bdef Multiply(a, b):return a * bdef Divide(a, b):return a / bdef Power(a, b):return a ** bdef Remainder(a, b):return a % boptions = {'+': ('Add', Add, '+'),'-': ('Subtract', Subtract, '-'),'*': ('Multiply', Multiply, '*'),'/': ('Divide', Divide, '/'),'^': ('Power', Power, '**'),'%': ('Remainder', Remainder, '%'),'#': ('Terminate', None)}while True:print('Select operation: ')for i, (k, v) in enumerate(options.items(), 1):print(f'{i}. {v[0]:<10}: {k} : ')option = input(f'Enter choice ({",".join(options.keys())}) : ')if control := options.get(option):_, func, *disp = controlif not func:breaka = input('Enter first number: ')b = input('Enter second number: ')try:a = float(a)b = float(b)print(f'{a} {disp} {b} = {func(a, b)}')except (ValueError, ZeroDivisionError) as e:print(e)else:print('Invalid option!')