Django: Utilização de Local Flavor no Admin

gistfile1.txt

from django.contrib import admin
from django.contrib.localflavor.br.forms import BRZipCodeField
from django.forms import ModelForm
from app.customers.models import Customer, Contact

class ContactInline(admin.TabularInline):
    model = Contact
    extra = 2
    
class CepForm(ModelForm):
    class Meta:
        model = Customer

    def __init__(self, *args, **kwargs):
        super(CepForm, self).__init__(*args, **kwargs)
        self.fields['postal_code'] = BRZipCodeField()

class CustomerAdmin(admin.ModelAdmin):
    inlines = [ContactInline, ]
    form = CepForm

admin.site.register(Customer, CustomerAdmin)

class CepForm(ModelForm):
    postal_code = BRZipCodeField()

    class Meta:
        model = Customer

ModelForm é um Form normal... vc pode simplesmente redefinir um determinado FormField.

Atualizando como ficou:

• models.py

...
from django.contrib.localflavor.br.forms import BRCPFField, BRCNPJField, BRZipCodeField
from django.forms import ModelForm

...
class BrFields(ModelForm):
    personal_document = BRCPFField(label='CPF')
    corporate_document = BRCNPJField(label='CNPJ', required=False)
    postal_code = BRZipCodeField(label='CEP')

    class Meta:
        model = Customer

• admin.py

from django.contrib import admin
from app.customers.models import Customer, Contact, BrFields
...
class CustomerAdmin(admin.ModelAdmin):
    ...
    form = BrFields

admin.site.register(Customer, CustomerAdmin)