audio_length = models.CharField(_('audio length'), blank=True, max_length=8)
preview = models.BooleanField(_('preview'), default=False)
preview_until = models.DateField(_('preview until'), blank=True, null=True)
audio_length = models.CharField(_('audio length'), blank=True, max_length=8)
preview = models.BooleanField(_('preview'), default=False)
preview_until = models.DateField(_('preview until'), blank=True, null=True)