Как улучшить код?

import math
from operator import *
 
#Functions for the calculating
def calc():
    select = input("Select an operator: + - * / ** √\n")
    operators = ["+", "-", "*", "/", "**"]
    try:
        if select == "√":
            root = float(input("Enter a number..."))
            print("√", root,"=", math.sqrt(root))
        elif select in operators:
            num1 = float(input("Enter the first number...\n"))
            num2 = float(input("Enter the second number...\n"))
            if select == "+":
                print(num1, "+",num2,"=", add(num1, num2))
            elif select == "-":
                print(num1, "-",num2,"=", sub(num1, num2))
            elif select == "*":
                print(num1, "*",num2,"=",  mul(num1, num2))
            elif select == "/":
                print(num1, "/",num2,"=", div(num1, num2))
            elif select == "**":
                print(num1, "**",num2,"=", pow(num1, num2))
            else:
                print("Error, invalid input")
    except:
        print("Error, you need to enter a number")
 
#The main function which use a while loop
def main():
    i = 0
    while True:
        if i == 0:
            calc()
        #print('\nCalculation finished. Do another? (Y/N)')
        selector = input("Calculation finished. Do another? (Y/N)\n")
        if selector.lower() == 'n':
            break
        elif selector.lower() == 'y':
            calc()
        i = 1
 
#About the script, here I use the main function
print("This is a simple calculator on python")
main()