models.py

    valid_end_time = models.DateTimeField(
            verbose_name=_("End valid period"),
            help_text=_("If not blank, date and time at which this exam ticket "
                "stops being valid/usable"),
            null=True, blank=True)
    restrict_to_facility = models.CharField(max_length=200, blank=True, null=True,
            verbose_name=_("Restrict to facility"),
            help_text=_("If not blank, this exam ticket may only be used in the "
                "given facility"))

    class Meta:
        verbose_name = _("Exam ticket")
        verbose_name_plural = _("Exam tickets")
        ordering = ("exam__course", "-creation_time")
        permissions = (
                ("can_issue_exam_tickets", _("Can issue exam tickets to student")),
                )

    def __unicode__(self):
        return _("Exam  ticket for %(participation)s in %(exam)s") % {
                "participation": self.participation,
                "exam": self.exam,
                }

    __str__ = __unicode__

    def clean(self):
        super().clean()

        try:
            if self.exam.course != self.participation.course:
                raise ValidationError(_("Participation and exam must live "
                        "in the same course"))
        except ObjectDoesNotExist:
            pass

# }}}

# vim: foldmethod=marker