[Persistence-sig] A simple Observation API

[Barry A. Warsaw]

>>>>> "NS" == Niki Spahiev <niki@vintech.bg> writes:

    | def addDate(self, date):
    |     self._p_changed = 1
    |     self.dates.append(date)  # self.dates is a simple list
    |     self.dates.sort()
    |     self._p_changed = 1

    NS> _p_changed before *and* after?

Seems unnecessarily redundant.  IIUC, setting _p_changed to 1 will
register the object so setting it twice simply registers it twice,
which doesn't seem very useful.  I guess when to set _p_changed will
be a decision that the object designer will have to make based on the
semantics of the object, and the operation.

-Barry