How to use the awscrt.http.HttpHeaders function in awscrt

def test_add_multi_values(self):
        h = HttpHeaders()
        h.add('Cookie', 'a=1')
        h.add('Cookie', 'b=2')
        self.assertEqual('a=1', h.get('Cookie'))
        self.assertEqual(['a=1', 'b=2'], list(h.get_values('Cookie')))

credentials_provider = awscrt.auth.AwsCredentialsProvider.new_static(
            SIGV4TEST_ACCESS_KEY_ID, SIGV4TEST_SECRET_ACCESS_KEY, SIGV4TEST_SESSION_TOKEN)

        signing_config = awscrt.auth.AwsSigningConfig(
            algorithm=awscrt.auth.AwsSigningAlgorithm.SigV4Header,
            credentials_provider=credentials_provider,
            region=SIGV4TEST_REGION,
            service=SIGV4TEST_SERVICE,
            date=SIGV4TEST_DATE,
            body_signing_type=awscrt.auth.AwsBodySigningConfigType.BodySigningOff)

        http_request = awscrt.http.HttpRequest(
            method=SIGV4TEST_METHOD,
            path=SIGV4TEST_PATH,
            headers=awscrt.http.HttpHeaders(SIGV4TEST_UNSIGNED_HEADERS))

        signing_future = awscrt.auth.aws_sign_request(http_request, signing_config)

        signing_result = signing_future.result(TIMEOUT)

        self.assertIs(http_request, signing_result)  # should be same object

        self.assertEqual(SIGV4TEST_METHOD, http_request.method)
        self.assertEqual(SIGV4TEST_PATH, http_request.path)

        # existing headers should remain
        for prev_header in SIGV4TEST_UNSIGNED_HEADERS:
            self.assertIn(prev_header, http_request.headers)

        # signed headers must be present
        for signed_header in SIGV4TEST_SIGNED_HEADERS:

def _test_put(self, secure):
        self._start_server(secure)
        connection = self._new_client_connection(secure)
        test_asset_path = 'test/test_http_client.py'
        with open(test_asset_path, 'rb') as outgoing_body_stream:
            outgoing_body_bytes = outgoing_body_stream.read()
            headers = HttpHeaders([
                ('Content-Length', str(len(outgoing_body_bytes))),
            ])

            # seek back to start of stream before trying to send it
            outgoing_body_stream.seek(0)

            request = HttpRequest('PUT', '/' + test_asset_path, headers, outgoing_body_stream)
            response = Response()
            http_stream = connection.request(request, response.on_response, response.on_body)

            # wait for stream to complete
            stream_completion_result = http_stream.completion_future.result(self.timeout)

            self.assertEqual(200, response.status_code)
            self.assertEqual(200, stream_completion_result)

def test_iter(self):
        # test that we iterate over everything we put in
        src = [('Host', 'example.org'), ('Cookie', 'a=1')]
        h = HttpHeaders(src)
        for pair in h:
            src.remove(pair)
        self.assertEqual(0, len(src))

def test_add(self):
        h = HttpHeaders()
        h.add('Host', 'example.org')
        self.assertEqual('example.org', h.get('Host'))
        self.assertEqual(['example.org'], list(h.get_values('Host')))

def test_set(self):
        h = HttpHeaders()

        # create
        h.set('Host', 'example.org')
        self.assertEqual(['example.org'], list(h.get_values('Host')))

        # replace
        h.set('Host', 'example2.org')
        self.assertEqual(['example2.org'], list(h.get_values('Host')))

        # replace many
        h.add('Host', 'example3.org')
        h.add('Host', 'example4.org')
        h.set('Host', 'example5.org')
        self.assertEqual(['example5.org'], list(h.get_values('Host')))

def test_iter_order(self):
        # test that headers with multiple values are iterated in insertion order
        src = [('Cookie', 'a=1'), ('cookie', 'b=2')]
        h = HttpHeaders(src)
        gather = [pair for pair in h]

        # note this also compares that we preserved case of the names
        self.assertEqual(src, gather)

def __init__(self, method='GET', path='/', headers=None, body_stream=None):
        assert isinstance(headers, HttpHeaders) or headers is None

        if headers is None:
            headers = HttpHeaders()

        binding = _awscrt.http_message_new_request(headers)
        super(HttpRequest, self).__init__(binding, headers, body_stream)
        self.method = method
        self.path = path