{
  "messages": [
    {
      "attachment": {
        "type": "template",
        "payload": {
          "template_type": "button",
          "text": "I just bought some viagra tea bags, to stop my biscuit going soft.",
          "buttons": [
            {
              "type": "show_block",
              "block_names": ["Joke"],
              "title": "Tell me another joke"
            }
          ]
        }
      }
    }
  ]
}