'Sends a batch of messages into the specified topic. The limit to the number of
messages which may be present in the topic is governed by the message
size the MaxTopicSizeInMegaBytes. If this message will cause the topic
to exceed its quota, a quota exceeded error is returned and the
message will be rejected.
topic_name:
Name of the topic.
messages:
List of message objects containing message body and properties.'

def send_topic_message_batch(self, topic_name, messages=None):

    _validate_not_none('topic_name', topic_name)
    _validate_not_none('messages', messages)
    request = HTTPRequest()
    request.method = 'POST'
    request.host = self._get_host()
    request.path = (('/' + _str(topic_name)) + '/messages')
    request.headers.append(('Content-Type', 'application/vnd.microsoft.servicebus.json'))
    request.body = _get_request_body(json.dumps([m.as_batch_body() for m in messages]))
    (request.path, request.query) = self._httpclient._update_request_uri_query(request)
    request.headers = self._update_service_bus_header(request)
    self._perform_request(request)
