def METHOD_NAME(self, exclude=None):
    super().METHOD_NAME(exclude)
    for other in FoodEvent.objects.filter(
        Q(end__gte=self.start, end__lte=self.end)
        | Q(start=self.start, start__lte=self.start)
    ):
        if other.pk == self.pk:
            continue
        raise ValidationError(
            {
                "start": _("This event cannot overlap with {}.").format(other),
                "end": _("This event cannot overlap with {}.").format(other),
            }
        )