class Time:
    """A representation of a particular date and time."""
    
    def __init__(self, date, time):
        """Construct a Time object.
        
        Parameters:
            self: the Time object
            date: a string in YYYY?MM?DD format
            time: a string in HH?MM?SS.S...S format
            
        Return value: the new Time object
        """
        
        pass
        
    def duration(self, otherTime):
        """Return the number of seconds elapsed between self and otherTime."""
        
        pass
        
    def date(self):
        """Return a YYYY-MM-DD string representation of the date."""
        
        pass
        
    def time(self):
        """Return a HH-MM-SS string representation of the time."""
        
        pass
        
    def __str__(self):
        """Return a YYYY-MM-DD HH:MM:SS string representation of the date and time."""
        
        pass