Month.py

from functools import total_ordering
from calendar import monthrange
import datetime
@total_ordering

class Month:
    __slots__ = ['year','month', 'first_day', 'last_day']

    def __init__(self,year,month):
        super().__setattr__("year", year)
        super().__setattr__("month", month)
        super().__setattr__("first_day", datetime.date(self.year, self.month, 1))
        weeks, days = monthrange(year, month)
        super().__setattr__("last_day", datetime.date(self.year, self.month, days))
    # @property
    # def year(self):
    #     year, month = self._dt
    #     return year

    # @property
    # def month(self):
    #     year, month = self._dt
    #     return month

    def __delattr__(self, name: str) -> None:
        raise AttributeError(f"{type(self).__name__} cannot delete {name}")

    def __setattr__(self, name, value):
        raise AttributeError(f'{type(self).__name__} cannot modify {name}.')
    def __key(self):
        return ((self.year, self.month))

    def __hash__(self):

        return hash(self.__key())
        
    def _is_valid_operand(self, other):
        if not hasattr(other,"year") or not hasattr(other,"month"):
            return False
        else:
            return True
 
    def __eq__(self,other):
        if not self._is_valid_operand(other):
            return False
        else:
            return self.__repr__() == other.__repr__()
    def __lt__(self, other):
        if not self._is_valid_operand(other):
            raise TypeError
        return( (self.year, self.month) < (other.year, other.month))
    def __repr__(self):
        return(f'{type(self).__name__}({self.year},{self.month})')

    def __str__(self):
        return(f'{self.year:04}-{self.month:02}')

    @classmethod
    def from_date(self,dt):
        year, month, day, *_ = datetime.date.timetuple(dt)
        return Month(year, month)

    def strftime(self, format):
        return datetime.datetime.strftime(datetime.datetime(self.year, self.month, 1),format)

if __name__ == "__main__":
    dec99 = Month(1999, 12)
    print(hash(dec99))
    jan01=Month(2001,1)
    print(dec99)
    print(jan01)
    print( sorted([Month(1998, 12), Month(2000, 1), Month(1999, 12)]))
    m1=Month(1998, 12)
    m2=Month(1998,12)
    print
    print(f"Equality - {m1} == {m2} {m1 == m2} ")
    t1=(1998,12)
    print(f"({m1} == {t1}) {m1 == t1}")
    try:
        print(m1 < t1)
    except TypeError:
        print(f"Success - TypeError on {m1} < {t1}")
    else:
        print(f"ERROR - No Zero Division on {m1} < {t1}")
    dec99 = Month(1999, 12)
    print(f'First day of {dec99} is {dec99.first_day}')
    print(f'Last day of {dec99} is {dec99.last_day}')
    nye99 = datetime.date(1999, 12, 31)
    dec99 = Month.from_date(nye99)
    print(f"Month from {nye99} is {dec99}")
    print(f"strftime of {dec99} is {dec99.strftime('%b %Y')}")
    try: 
        dec99.year = 1998
    except AttributeError:
        print("Success - got an Attribute Error when trying to change dec99.year")
    else:
        print("FAILURE - Did not get attribute Error when trying to change {dec99.year}")
    dic = {Month(1999, 12), dec99, Month(2000, 1)}
    print(f'Created Dic: {dic}')