new_contents: from datetime import date, datetime
  
  import pytz
  from django.test import TestCase
  
  from django_afip import parsers
  
  
  class ParseDatetimeTestCase(TestCase):
      def test_parse_null(self):
          self.assertEqual(parsers.parse_datetime('NULL'), None)
  
      def test_parse_none(self):
          self.assertEqual(parsers.parse_datetime(None), None)
  
      def test_parse_datetimes(self):
          tz = pytz.timezone(pytz.country_timezones['ar'][0])
          self.assertEqual(
              parsers.parse_datetime('20170730154330'),
              datetime(2017, 7, 30, 15, 43, 30, tzinfo=tz),
          )
  
  
  class ParseDateTestCase(TestCase):
      def test_parse_null(self):
          self.assertEqual(parsers.parse_date('NULL'), None)
  
      def test_parse_none(self):
          self.assertEqual(parsers.parse_date(None), None)
  
      def test_parse_dates(self):
          self.assertEqual(
              parsers.parse_date('20170730'),
              date(2017, 7, 30),
          )
  
subject: Add tests for parse_date and parse_datetime