Правильное использование функций в Python 3.7

Question

Я пытаюсь использовать несколько вариантов калькулятора.Я думал, что создание функций для каждого отдельного вычисления и в зависимости от пользовательского ввода будет выполнять определенную функцию.После запуска кода и после получения пользовательского ввода он не выполняет функцию так, как мне бы хотелось, чтобы она выполнялась.Куда я иду не так?Заранее благодарим за то, что уделили время ознакомлению с моей работой.

Пока мой код:

# WE ARE TRYING TO SPLIT THE OPTIONS INTO FUNCTIONS THAT CAN BE CALLED LATER DEPENDING ON THE INPUT
# SETS THE USER INPUT INTO VARIABLES AS 'int' OR 'float' THAT CAN BE USED IN LATER FORMULAS
def calc_int():
    principal = int(input("What is the principal amount?"))
    rate = float(input("What is the rate amount? (Enter in decimal format)"))
    number = int(input("How many times will this be compounded yearly?"))
    time = int(input("How long will this be compounded for?"))

    # CALCULATES THE COMPOUND INTEREST AMOUNT
    exponent = number * time
    interest_amount = principal * (1 + rate / number) ** exponent

    # CALCULATES HOW MUCH WAS EARNED OR LOST
    earned_amount = interest_amount - principal

    # THIS WILL DETERMINE THE COMPOUND AMOUNT FOR EACH TERM
    term_1 = principal * rate * time
    new_amount_term_1 = term_1 + principal
    # Term_2 = New_Amount_Term_1 * rate * time_i
    # New_Amount_Term_2 = Term_2 + New_Amount_Term_1

    print("The interest amount is:")
    print(interest_amount)
    print("The amount earned is:")
    print(earned_amount)

    print("")
    print("Term 1 amount is:")
    print(term_1)
    print("The ending balance for that term is:")
    print(new_amount_term_1)

    print("")
    print("Term 2 amouunt is:")
    # print(Term_2)
    print("working on it")
    print("The ending balance or that term is:")
    # print(New_Amount_Term_2)
    print('working on it')


def calc_fahr():
    # LETS GET THE CELSIUS AMOUNT THAT WE ARE CONVERTING
    celsius = int(input("What is the celsius amount?"))

    # NOW LETS MAKE THE CALCULATION
    fahrenheit = (9 * celsius) / 5 + 32

    # PRINTS THE CONVERTED VALUE
    print(celsius, "celsius is equal to", fahrenheit, "fahrenheit")


def calc_cel():
    # RETRIEVE THE FAHRENHEIT AMOUNT THAT WILL BE CONVERTED
    fahrenheit = int(input("What is the fahrenheit amount?"))

    # THIS CONVERTS THE INPUTED AMOUNT TO FAHRENHEIT
    celsius = (fahrenheit - 32) * 5 / 9

    # PRINTS THE CONVERTED VALUE
    return fahrenheit, "fahrenheit is equal to", celsius, "celsius"


# LETS FIGURE OUT WHAT THEY WANT TO DO
print("Welcome! What are we calculating today?")
print("Make a wise choice!")
print("0 - Interest")
print("1 - Fahrenheit")
Answer_1 = input("2 - Celsius")

# NOW LETS FIGURE OUT WHAT THEY CHOSE AND MOVE OVER TO THAT SECTION
if Answer_1 == 0:
    calc_int()
elif Answer_1 == 1:
    calc_fahr()
elif Answer_1 == 2:
    calc_cel()