python - how do I access a django form value in the __init__ method for a query -

i have model includes foreign key:

class part(models.model):     parttype = models.foreignkey(parttype, on_delete=models.cascade)     brand = models.foreignkey(brand, on_delete=models.cascade)     part_name = models.charfield(max_length=60)  class quotepart(models.model):     quote = models.foreignkey(quote, on_delete=models.cascade)     line = models.positivesmallintegerfield(default=1)     parttype = models.foreignkey(parttype, on_delete=models.cascade)     # part can none if part has not been selected     part = models.foreignkey(part, on_delete=models.cascade,blank=true,null=true) 

i have form allows parts added quote , want want limit choices on form parts right parttype code not working:

    class quotebikepartform(modelform):     def __init__(self, *args, **kwargs):         super(quotebikepartform, self).__init__(*args, **kwargs)         self.fields['parttype'].widget.attrs['disabled'] = true         self.fields['frame_part'].widget.attrs['disabled'] = true         parttype = kwargs.pop('parttype')         self.fields['part'].queryset = part.objects.filter(parttype=parttype.pk)      class meta:         model = quotepart         fields = ['quote','line','parttype','frame_part', 'part', 'quantity','cost_price', 'sell_price']  quotebikepartformset = inlineformset_factory(quote, quotepart, form=quotebikepartform) 

i have tried number of different things , far no luck.

you can use 'self.instance.key_name' access value.