class Date:   
    """ a blueprint (class) for objects
        that represent calendar days
    """
    def __init__( self, mo, dy, yr ):
        """ the Date constructor """
        self.month = mo
        self.day = dy
        self.year = yr

    def __str__( self ):
        """ used for printing Dates """
        s = "{:02d}/{:02d}/{:04d}".format(self.month,self.day,self.year)
        return s

    def is_leap_year( self ):
        """ anyone know the rule? 
            Every year that is divisible by 4 is a leap year
            However, a year that is divisible by 100 is NOT a leap year
            However, a year that is divisible by 400 IS a learp year
        """
        if self.year % 400 == 0:
            return True
        if self.year % 100 == 0:
            return False
        return self.year % 4 == 0

    def is_before(self, d2):
        """ if self is before d2, returns True; otherwise returns False"""
        '''This version is probamatic'''
        if self.year < d2.year:
            return True
        else:
            return False

        if self.month < d2.month:
            return True
        else:
            return False

        if self.day < d2.day:
            return True
        else:
            return False

        return False

    def is_before(self, d2):
        """ if self is before d2, returns True; otherwise returns False"""

        '''This version works correctly'''
        if self.year < d2.year:
            return True
 
        if self.month < d2.month and self.year == d2.year: 
            return True

        if self.day < d2.day and self.month == d2.month:
            return True

        return False

    def set_year( self, yr ):
        """
        Set the year value
        """
        self.year = yr

    def set_month( self, mo ):
        """
        Set the month value
        """
        self.month = mo

    def set_day( self, dy ):
        """
        Set the day value
        """
        self.day = dy

d = Date( 11, 8, 2011 )
print( d )                 # 11/08/2011
print( d.is_leap_year() )  # False

d2 = Date( 1, 1, 2012 )
print( d2 )                # 01/01/2012
print( d2.is_leap_year() )   # True