设计一个表示分数的类Fraction。这个类用两个int类型的变量分别表示分子和分母。注意，在创建和做完运算后应该化简分数为最简形式。如2/4应该被化简为1/2。

好的，以下是Fraction类的代码实现：

class Fraction:
    def __init__(self, numerator, denominator):
        self.numerator = numerator
        self.denominator = denominator
        self.reduce()

    def __str__(self):
        return str(self.numerator) + '/' + str(self.denominator)

    def reduce(self):
        gcd = self.gcd(self.numerator, self.denominator)
        self.numerator //= gcd
        self.denominator //= gcd

    def gcd(self, a, b):
        if b == 0:
            return a
        else:
            return self.gcd(b, a % b)

    def __add__(self, other):
        new_numer = self.numerator * other.denominator + other.numerator * self.denominator
        new_denom = self.denominator * other.denominator
        return Fraction(new_numer, new_denom)

    def __sub__(self, other):
        new_numer = self.numerator * other.denominator - other.numerator * self.denominator
        new_denom = self.denominator * other.denominator
        return Fraction(new_numer, new_denom)

    def __mul__(self, other):
        new_numer = self.numerator * other.numerator
        new_denom = self.denominator * other.denominator
        return Fraction(new_numer, new_denom)

    def __truediv__(self, other):
        new_numer = self.numerator * other.denominator
        new_denom = self.denominator * other.numerator
        return Fraction(new_numer, new_denom)

这个类有一个构造函数，以及__str__方法重载了打印输出的行为，便于观察结果。reduce方法用于将分数化为最简形式。gcd方法用于求分子和分母的最大公约数，方便化简分数。加、减、乘、除操作都被重载了。