def METHOD_NAME(self):
    """Doesn't let you specify a keyword twice (here 'case_name')"""
    with self.assertRaises(CaseBlockError) as context:
        CaseBlock(
            case_id=self.CASE_ID,
            case_name='Johnny',
            update={'case_name': 'Johnny'},
        ).as_xml()
    self.assertEqual(six.text_type(context.exception), "Key 'case_name' specified twice")