def METHOD_NAME(self):
    class TestForm(PhoneNumberMixin, AbstractAddressForm):
        phone_number_fields = {
            "phone_number": {
                "required": False,
                "help_text": "",
                "max_length": 32,
                "label": "Phone number",
            }
        }
        class Meta:
            model = ShippingAddress
            fields = ["country", "phone_number", "postcode"]
    CountryFactory(iso_3166_1_a2="GB", is_shipping_country=True)
    form = TestForm(
        data={"phone_number": "123456", "country": "GB", "postcode": "WW1 2BB"}
    )
    self.assertFalse(form.is_valid())
    self.assertEqual(
        form.errors["phone_number"],
        ["This is not a valid local phone format for UNITED KINGDOM."],
    )