本题自定义一个分数类，类名Fraction，包含分子num和分母den，定义如下

好的，以下是Fraction类的定义：

class Fraction:
    def __init__(self, num, den):
        self.num = num
        self.den = den

    def __str__(self):
        return f"{self.num}/{self.den}"

    def __add__(self, other):
        num = self.num * other.den + self.den * other.num
        den = self.den * other.den
        return Fraction(num, den)

    def __sub__(self, other):
        num = self.num * other.den - self.den * other.num
        den = self.den * other.den
        return Fraction(num, den)

    def __mul__(self, other):
        num = self.num * other.num
        den = self.den * other.den
        return Fraction(num, den)

    def __truediv__(self, other):
        num = self.num * other.den
        den = self.den * other.num
        return Fraction(num, den)

    def __eq__(self, other):
        return self.num * other.den == self.den * other.num

    def __lt__(self, other):
        return self.num * other.den < self.den * other.num

    def __gt__(self, other):
        return self.num * other.den > self.den * other.num

    def __le__(self, other):
        return self.num * other.den <= self.den * other.num

    def __ge__(self, other):
        return self.num * other.den >= self.den * other.num

Fraction类包含分子num和分母den两个属性，以及加、减、乘、除、比较等运算符的重载方法。我们可以使用这个类来进行分数的各种运算。