How to access formset filed Django

Question

I'm using inlineformset_factory. I need to check product in self.data and grab product value inside __init__ method. Unable grab formset filed value, please help.

class PurchaseOrderDetailsForm(forms.ModelForm):
    class Meta:
        model = PurchaseOrder_detail
        fields = ('product', 'product_attr', 'order_qnty', 'recvd_qnty', 'amount_usd', 'amount_bdt', 'unit_price', 'sales_price', 'commission_price')
        widgets = {
            'product': Select2Widget,
            'product_attr': Select2Widget,
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)  

        if 'product' in self.data:
            product_id = int(self.data.get('product'))
            self.fields['product_attr'].queryset = ProductAttributes.objects.filter(product_id=product_id)

Answer 1

等待大神解答