def METHOD_NAME(self):
    iot = InformatieObjectTypeFactory.create()
    # Create 2 documents with the same IOT
    io_1 = EnkelvoudigInformatieObjectFactory.create(
        informatieobjecttype__concept=False, informatieobjecttype=iot
    )
    io_1_url = f"http://testserver{reverse(io_1)}"
    io_2 = EnkelvoudigInformatieObjectFactory.create(
        informatieobjecttype__concept=False, informatieobjecttype=iot
    )
    io_2_url = f"http://testserver{reverse(io_2)}"
    # Relate a zaak to one of the documents
    zio = ZaakInformatieObjectFactory.create(informatieobject=io_1_url,)
    zio_url = reverse(zio)
    # Attempt to replace the document related to the zaak with another document
    response = self.client.patch(zio_url, {"informatieobject": io_2_url})
    self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
    validation_error = get_validation_errors(response, "informatieobject")
    self.assertEqual(validation_error["code"], IsImmutableValidator.code)