Ticket #24539: admin.py

from django.contrib import admin
from django.forms.models import modelform_factory

from .models import Product


@admin.register(Product)
class ProductAdmin(admin.ModelAdmin):

    def get_form(self, *args, **kwargs):
        class ProductForm(modelform_factory(Product, fields=['reference'])):

            def clean(self):
                # Implement some custom validation
                pass

        return ProductForm