Response card with attachment returned to Lex from Lambda doesn't contain attachment

Question

I use AWS Lambda function written in Python to return a response card with an attachment (according to https://docs.aws.amazon.com/lex/latest/dg/lambda-input-response-format.html#using-lambda-response-format and Hyperlink in response card button in Amazon Lex). However, I have no possibility to get access to the attachment, i.e. I can't click neither to the image nor to any other place to open the link.

Sample code is below and the result (including the response card) in on the image.
_{(source: imggmi.com)}

def close_response_card(session_attributes, fulfillment_state, message):
    return {
    'sessionAttributes': session_attributes,
    "dialogAction": {
        "type": "Close",
        "fulfillmentState": fulfillment_state,
        'message': message,
        "responseCard": {
            "version": 1,
            "contentType": "application/vnd.amazonaws.card.generic",
            'genericAttachments': [
                {
                    'title': 'Here is a list of hospitals',
                    'subTitle': 'Below is a map',
                    'attachmentLinkUrl': 'https://www.google.com/maps/search/?api=1&query=nearby+hospitals',
                    'imageUrl': 'https://images.sftcdn.net/images/t_optimized,f_auto/p/95612986-96d5-11e6-af7c-00163ec9f5fa/3771854867/google-maps-screenshot.png'
            }
        ]
     }
  }
    }

I'd like to create a card which lets the user downloads some file after he or she clicks on the card.