Customise message to slack

Rasa Open Source
1

Hi

I am using slack for my bot. I can send text message to the bot using dispatcher.utter_template(“utter_stores_found”, tracker)

                    dispatcher.utter_message(store_list).

But how can i customize a message as described in [Attaching content and links to messages | Slack(http://Attaching content and links to messages)

I tried dispatcher.utter_attachment() dispatcher.utter_custom_message()

but no luck. Any idea guys.

Thanks