python - Django クエリセット ManytoMany および OnetoMany

Question

私はこのmodels.pyを持っています

class Sitename(models.Model): 
   #id              = models.AutoField(primary_key=True)  ## to be removed
    site            = models.CharField()                  ## find values

class Equipment(models.Model):
   #id              = models.AutoField(primary_key=True)  ## to be removed
    serialno        = models.CharField()                  ## known values

class RSL(models.Model): ##Radio Station License
   #id              = models.AutoField(primary_key=True)  ## to be removed
    sitename        = models.ForeignKey(Sitename)
    equipment       = models.ManyToManyField(Equipment)

しか知りEquipment serialnoませんが、適切なクエリセットがわかりませんか? これまでのところ、外部キーを照会する方法を知っています。

sn       = 'abc'

equip    = Equipment.objects.get(serialno=sn)
rsl      = RSL.objects.?????
sitename = Site.objects.get(pk=rsl.pk)