def __add__(self, polynomial_2: Polynomial) -> Polynomial:

        if self.degree > polynomial_2.degree:
            coefficients = self.coefficients[:]
            for i in range(polynomial_2.degree + 1):
                coefficients[i] += polynomial_2.coefficients[i]
            return Polynomial(self.degree, coefficients)
        else:
            coefficients = polynomial_2.coefficients[:]
            for i in range(self.degree + 1):
                coefficients[i] += self.coefficients[i]
            return Polynomial(polynomial_2.degree, coefficients)