Django ManytoMany小部件到CheckboxSelectMultiple和链式查询集

Question

碰巧我需要将ManytoMany字段显示为CheckboxSelectMultiple，没问题。技巧部分是要显示默认字段，用户应该能够添加新选项，此选项应显示在表单上。

这是我做的：

models.py

class Feature(models.Model):
   name = models.CharField( _("Feature Name"), max_length=40)
   default = models.BooleanField(_("Is Global Feature"), default = False)

class SomeModel(models.Model):
   features = models.ManyToManyField(Feature, related_name='features')

forms.py

class FeatureForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
    somemodel = kwargs['somemodel']
    kwargs.pop('somemodel')
    super(SpaFeatureForm, self).__init__(*args, **kwargs)
    default_features = Feature.objects.filter(default=True)
    custom_features = somemodel.features.filter(default=False)
    q_set = QuerySetChain(default_features, custom_features)
    self.fields['features'].widget = forms.CheckboxSelectMultiple()
    self.fields['features'].queryset = q_set

class Meta:
    model = m.Spa
    fields = ('features',)

我仍然会实现第二部分，它将是一个功能表单和某些js来填充Checkbox Multiselect字段选项。

---

我修改了@akaihola answer如何链接查询集，将def _all更改为def all。它运作良好。

现在的问题是：这是最好的解决方案吗？