How to use the apiron.client.get_required_headers function in apiron

def test_get_required_headers(self, mock_endpoint):
        service = mock.Mock()
        service.required_headers = {"one": "two"}
        mock_endpoint.required_headers = {"foo": "bar"}
        expected_headers = {}
        expected_headers.update(service.required_headers)
        expected_headers.update(mock_endpoint.required_headers)
        assert expected_headers == client.get_required_headers(service, mock_endpoint)