'Update the DB snapshot\'s status information by making a call to fetch
the current snapshot attributes from the service.
:type validate: bool
:param validate: By default, if EC2 returns no data about the
instance the update method returns quietly.  If
the validate param is True, however, it will
raise a ValueError exception if no data is
returned from EC2.'

def update(self, validate=False):

    rs = self.connection.get_all_dbsnapshots(self.id)
    if (len(rs) > 0):
        for i in rs:
            if (i.id == self.id):
                self.__dict__.update(i.__dict__)
    elif validate:
        raise ValueError(('%s    is    not    a    valid    Snapshot    ID' % self.id))
    return self.status
