def METHOD_NAME(self):
    """
    Test language code set to null which shoul direct to default language "en"
    """
    lang_code = self._get_inactive_language_code()
    response = self.client.post(reverse("set_language"), self.set_post_data(lang_code), content_type='application/json')
    self.assertEqual(response.status_code, 200)
    self.assertEqual(
        response.content.decode("utf-8"),
        translate_url(reverse("base"), lang_code),
    )
    self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
    lang_code = None
    response = self.client.post(reverse("set_language"), self.set_post_data(lang_code), content_type='application/json')
    self.assertEqual(response.status_code, 200)
    self.assertEqual(
        response.content.decode("utf-8"),
        translate_url(reverse("base"), "en"),
    )
    self.assertFalse(LANGUAGE_SESSION_KEY in self.client.session)