MySimplePythonApplication is not working What's wrong?

The program outputs: a, not what the Tutorial said I should expect. Code as follows:
import math

__author__ = 'Ralph'


class Solver:
    def demo(self) -> object:
        """
   
            :rtype : object     #Same result with or without "rtype object"
            """
        while True:
            a = int(input("a "))  # Program terminates with output: a
            b = int(input("b "))  # Same result with (") or (')
            c = int(input("c "))
            d = b ** 2 - 4 * a * c
            if d >= 0:
disc = math.sqrt(d)
root1 = (-b + disc) / (2 * a)
root2 = (-b - disc) / (2 * a)
print(root1, root2)
            else:
print('error')


Solver().demo()
Could not get 'code' to 'paste' into 'Attachments'. Any help is appreciated.