calculator_refactorized.py

import re

print("\n\033[38;1mCalcular +, , *, / de 2 números:\033[0m\n")

def solve(str_operation):
    pattern = re.compile("([0-9]+)[\s]*([\+\-\/\*])[\s]*([0-9]+)")
    match = pattern.match(str_operation)
    (operator1, operation, operator2) = match.groups()

    if operation == "+":
        return int(operator1) + int(operator2)
    elif operation == "-":
        return int(operator1) - int(operator2)
    elif operation == "/":
        return int(operator1) / int(operator2)
    elif operation == "*":
        return int(operator1) * int(operator2)
    else:
        return None;

# Loop Infinito
while True:
    operation = input("Ingerese una oparacion o q para salir: ")
    if operation == "q":
        break;
    else:
        result = solve(operation)
        if result == None:
            print ("Operacion no permitida\n")
        else:
            print("\033[38;1m" + str(result) + "\033[0m\n")