def METHOD_NAME(self):
    self.component.project.add_user(self.user, "Administration")
    self.component.language_regex = "^cs$"
    self.component.save()
    # One chosen
    response = self.client.post(
        reverse("new-language", kwargs=self.kw_component),
        {"lang": "af"},
        follow=True,
    )
    self.assertContains(
        response, "The given language is filtered by the language filter."
    )