要比较两个日期，可以创建一个继承自日期类的时间类。下面是一个示例代码：

from datetime import datetime

class Date:
    def __init__(self, year, month, day):
        self.year = year
        self.month = month
        self.day = day
        
    def __lt__(self, other):
        if isinstance(other, Date):
            return datetime(self.year, self.month, self.day) < datetime(other.year, other.month, other.day)
        else:
            raise TypeError("Cannot compare Date with non-Date object.")
    
    def __gt__(self, other):
        if isinstance(other, Date):
            return datetime(self.year, self.month, self.day) > datetime(other.year, other.month, other.day)
        else:
            raise TypeError("Cannot compare Date with non-Date object.")
    
    def __eq__(self, other):
        if isinstance(other, Date):
            return datetime(self.year, self.month, self.day) == datetime(other.year, other.month, other.day)
        else:
            raise TypeError("Cannot compare Date with non-Date object.")

class Time(Date):
    def __init__(self, year, month, day, hour, minute, second):
        super().__init__(year, month, day)
        self.hour = hour
        self.minute = minute
        self.second = second
        
    def __lt__(self, other):
        if isinstance(other, Time):
            return datetime(self.year, self.month, self.day, self.hour, self.minute, self.second) < datetime(other.year, other.month, other.day, other.hour, other.minute, other.second)
        else:
            raise TypeError("Cannot compare Time with non-Time object.")
    
    def __gt__(self, other):
        if isinstance(other, Time):
            return datetime(self.year, self.month, self.day, self.hour, self.minute, self.second) > datetime(other.year, other.month, other.day, other.hour, other.minute, other.second)
        else:
            raise TypeError("Cannot compare Time with non-Time object.")
    
    def __eq__(self, other):
        if isinstance(other, Time):
            return datetime(self.year, self.month, self.day, self.hour, self.minute, self.second) == datetime(other.year, other.month, other.day, other.hour, other.minute, other.second)
        else:
            raise TypeError("Cannot compare Time with non-Time object.")

# 示例用法
date1 = Date(2021, 1, 1)
date2 = Date(2022, 1, 1)
time1 = Time(2021, 1, 1, 12, 0, 0)
time2 = Time(2021, 1, 1, 15, 0, 0)

print(date1 < date2)  # 输出: True
print(date1 == date2)  # 输出: False
print(time1 < time2)  # 输出: True
print(time1 == time2)  # 输出: False

在上面的示例中，我们创建了一个Date类来表示日期，然后创建了一个Time类来表示日期和时间。Time类继承自Date类，因此可以直接使用Date类中定义的比较方法。

在比较方法中，我们使用datetime模块的datetime类来进行日期和时间的比较。datetime类提供了比较运算符来比较两个日期和时间的大小关系。

注意，在比较方法中我们还添加了类型检查和错误处理，如果比较的对象不是Date或Time类型的，会抛出TypeError异常。

最后，我们展示了如何使用这些类来比较两个日期和时间的大小关系。