code: def diff(self, dt=None, abs=True):
          
          if dt is None:
              dt = self.today()
  
          return Period(self, Date(dt.year, dt.month, dt.day), absolute=abs)
docs: Returns the difference between two Date objects as a Period.
  
          :type dt: Date or None
  
          :param abs: Whether to return an absolute interval or not
          :type abs: bool
  
          :rtype: Period