Python实现一元二次方程的定义是：ax2 + bx + c = 0 请编写一个函数，返回一元二次方程的解。

<strong><span style="font-size:18px;">#杨鑫newlifeimport mathdef quadratic_equation(a, b, c):    t = math.sqrt(pow(b, 2) - 4 * a * c)    if(pow(b, 2) - 4 * a * c) > 0:        return (-b + t) / (2 * a), (-b - t) / (2 * a)    elif (pow(b, 2) - 4 * a * c) == 0:         return (-b + t) / (2 * a)    else:    return Noneprint quadratic_equation(2, 3, 0)print quadratic_equation(1, -6, 5)</span></strong>