README.rst listening code bug due to message schema

[Quemoy]

Hello. In README.rst, a suggested sample code for listening to message is:

def callback(message, subscription_id):
    print('Subscription ID: {}: Message: {}'.format(subscription_id, message.data.__str__()))
    return True  # If desired return False to stop the message flow. This will unblock the process as well.

listener.listen(callback, maximum_messages=10)  # Omitting maximum_messages means you will continue to get messages as they appear. Can be a firehose. Use with caution.
# You may pass subscription ID as a parameter to the listen function

However, using this code produces the following error:

Input In [1], in callback(message, subscription_id)
      8 def callback(message, subscription_id):
      9     print('Subscription ID: {}: Message: {}'.format(subscription_id, 
---> 10                                                     message.data.__str__()))
     11     return True

AttributeError: 'dict' object has no attribute 'data'

This seems like because the schema for a message is different. This is what a message looks like from the streams:

{'an': 'DUBQTELH20230317ej3g00046', 'document_type': 'article', 'action': 'del', 's
ource_code': 'DUBQTELH', 'source_name': 'Telegraph Herald', 'publication_date': '2023-03-16T00:00:00
.000Z', 'publication_datetime': '2023-03-16T00:00:00.000Z', 'modification_date': '2023-03-20T04:33:5
9.600Z', 'modification_datetime': '2023-03-20T04:33:43.000Z', 'ingestion_datetime': '2023-03-20T04:3
3:43.000Z', 'attrib_code': 'DUBQTELH', 'authors': [], 'clusters': []}

e.g., there's no longer a data field in the message.

The code in the demo directory does not seem to have this problem. However, the documentation on the developer platform does say that a message has a 'data' field.