def cuts_time(self):
        # get total time in seoonds of video based on selected cuts.
        # or None if there are no clips.
        cuts = Cut_List.objects.filter(episode=self, apply=True)
        if not cuts:
            ret = None
        else:
            s=0
            for cut in cuts:
                s+=int(cut.duration()) # durration is in seconds :p
            ret = s

        return ret