old_contents: from django.test import TestCase
  from django import forms
  from defendant.utils import is_valid_urn_format
  
  
  class UtilsTestCase(TestCase):
      urls = 'defendant.tests.urls'
      
      def test_is_valid_urn_format(self):
          good_URNs = [
              "00/AA/0000000/00",
              "12/bb/1234567/12",
              "06/JJ/50563/14",
              "06/JJ/50534/14",
          ]
          bad_URNs = [
              "123",
              "00bb/0000000/00",
              "AA/bb/0000000/00",
              "00/bb/000000/00",
              "0/bb/0000000/00",
              "00/bb/0000000/0",
          ]
          
          for URN in good_URNs:
              self.assertTrue(is_valid_urn_format(URN))
          
          for URN in bad_URNs:
              with self.assertRaises(forms.ValidationError):
                  is_valid_urn_format(URN)
new_contents: from django.test import TestCase
  from django import forms
  from defendant.utils import is_valid_urn_format
  
  
  class UtilsTestCase(TestCase):
      urls = 'defendant.tests.urls'
  
      def test_is_valid_urn_format(self):
          good_urns = [
              "00/AA/0000000/00",
              "12/bb/1234567/12",
              "06/JJ/50563/14",
              "06/JJ/50534/14",
          ]
          bad_urns = [
              "123",
              "00bb/0000000/00",
              "AA/bb/0000000/00",
              "00/bb/000000/00",
              "0/bb/0000000/00",
              "00/bb/0000000/0",
          ]
  
          for URN in good_urns:
              self.assertTrue(is_valid_urn_format(URN))
  
          for URN in bad_urns:
              with self.assertRaises(forms.ValidationError):
                  is_valid_urn_format(URN)
  
subject: Test for new URN styles