Django多对多关系报错：<title> object (None)>需要先设置id字段的值.

我在使用form.save(COMMIT=FALSE)时遇到错误，并且我找不出自己做错了什么.

我的观点是这样的:

views.py个

def make_electable(request, election_id):
    election = get_object_or_404(CommissionElection, id=election_id)
    if request.method == 'POST':
        form = MakeElectable(request.POST)
        if form.is_valid():
            electable = form.save(commit=False)
            electable.election.set(election)
            form.save()

forms.py个

class MakeElectable(forms.ModelForm):
    class Meta:
          model = ElectablePerson
          fields = ['commission',]
    commission = forms.ModelChoiceField(queryset=Commissie.objects.all(), widget=forms.RadioSelect())

models.py个

class CommissionElection(models.Model):
    title = models.CharField(max_length=64)
    commission = models.ManyToManyField(Commissie)
    electable_time = DateRangeField()
    voting_time = DateRangeField()


class ElectablePerson(models.Model):
    commission = models.CharField(max_length=128)
    election = models.ManyToManyField(CommissionElection)

我得到的错误是:

在使用这种多对多关系之前，"&lt；elecablePerson:Electric ablePerson Object(None)&gt；"需要有一个"id"字段的值.

我不明白为什么这个物体是空的.我怀疑这与许多其他领域有关.