《python语言程序设计》2018版第7章第06题代数：平方根 设计一个名为QuadraticEquation类

类代码部分

class QuadraticEquation:
    def __init__(self, a, b, c):
        self.a = a
        self.b = b
        self.c = c

    def set_a(self, a):
        self.a = a

    def get_a(self):
        return self.a

    def set_b(self, b):
        self.b = b

    def get_b(self):
        return self.b

    def set_c(self, c):
        self.c = c

    def get_c(self):
        return self.c

    def get_discrimination(self