django如何通过ManyToManyField过滤？

Question

我有模特：

class DamageKind(models.Model):
    # the possible regions for this kind of damage
    regions = models.ManyToManyField(Region)
    [...]

class Damage(models.Model):
    region = models.ForeignKey(Region)
    kind = forms.models.ModelChoiceField(queryset=???)
    [...]

如何获取仅包含selectet区域可能的damagekinds的查询集？

提前致谢