@property
def sessions(self):
    try:
        if (self._sessions is not None):
            return self._sessions
    except AttributeError:
        pass
    try:
        self._sessions = Session.objects.filter(id__in=self.get_session_ids())
    except ValueError:
        self._sessions = Session.objects.none()
    return self.sessions
@property
def sessions(self):
    try:
        if (self._sessions is not None):
            return self._sessions
    except AttributeError:
        pass
    try:
        self._sessions = Session.objects.filter(id__in=self.get_session_ids())
    except ValueError:
        self._sessions = Session.objects.none()
    return self.sessions