Calculator_trial.py

#operations
def a(x,y):
    return x + y

def m(x,y):
    return x * y

def s(x,y):
    return x - y

def d(x,y):
    try:
        return x / y
    except ZeroDivisionError:
        print ("Unable to divide by 0. Try another number.")

while True:
    try:
        x = float(input("Enter a number-->\n"))
        y = float(input("Enter another number-->\n"))

    except (ValueError, NameError):
        print ("Invalid input. Please try again.")
        continue

    try:
        o = input("Select an Operation-->  (+) (*) (-) (/)\n")

    except (ValueError, NameError):
        print ("Invalid Operation. Please try again. (+ or * or - or /)")
        continue

    if o == "+":
        ans = a(x,y)
    elif o == "*":
        ans = m(x,y)
    elif o == "-":
        ans = s(x,y)
    elif o == "/":
        ans = d(x,y)

    if y != 0:
        print ("Your answer is:")
        print ("x" , o , "y" , "=" , ans , sep=" ")
    else:
        continue

    while True:
        restart = input ("Run again? (y / n)")
        if restart == 'y':
            break
        elif restart != "n":
            print ("Invalid input. Type (y / n)")
            continue
        else:
            print ("Thanks for using my calculator!")
            quit()
    else:
        print("An unexpected error has occured. Terminating...")
        quit()