Calculator (Refactored)

def calculator():
        """
        calculates two input integers depending on assigned operator
        """

        while True: #Keeps the program looping
                first_number = int(raw_input("First number: "))
                operator = raw_input("Operator: ")
                second_number = int(raw_input("Second number: "))

                if operator == '+':
                        print first_number, operator, second_number, '=', float(first_number + second_number), "\n"
                elif operator == '-':
                        print first_number, operator, second_number, '=', float(first_number - second_number), "\n"
                elif operator == '*':
                        print first_number, operator, second_number, '=', float(first_number * second_number), "\n"
                elif operator == '/':
                        print first_number, operator, second_number, '=', float(first_number / second_number), "\n"
                else:
                        print "Invalid! Must be an operator!"