title: Slack chat.postMessage attachment gives no_text
body: <p>When I try to add an attachment to my message I either only get the text or if I leave out the text I get "error": "no_text", is there any way to send an attachmet with chat.postMessage?</p>
  
  <p>This is the python code I use for sending the message:</p>
  
  <pre><code>r = requests.post('https://slack.com/api/chat.postMessage', params=json.loads("""
      {
          "token": "xoxp-mytokenhere",
          "channel": "C4mychannelhere",
          "attachments": [
              {
                  "text": "Question?",
                  "fallback": "Question?",
                  "callback_id": "callback_id",
                  "color": "#3AA3E3",
                  "attachment_type": "default",
                  "actions": [
                      {
                          "name": "question",
                          "text": "Yes",
                          "style": "good",
                          "type": "button",
                          "value": "yes"
                      },
                      {
                          "name": "question",
                          "text": "Nope",
                          "style": "good",
                          "type": "button",
                          "value": "no"
                      }
                  ]
              }
          ]
      }
  """))
  </code></pre>
  
  <p>Based on the comment I went with the following solution:</p>
  
  <pre><code>r = requests.post('https://slack.com/api/chat.postMessage',     params=json.loads({
          "token": "xoxp-mytokenhere",
          "channel": "C4mychannelhere",
          "attachments": json.dumps([
              {
                  "text": "Question?",
                  "fallback": "Question?",
                  "callback_id": "callback_id",
                  "color": "#3AA3E3",
                  "attachment_type": "default",
                  "actions": [
                      {
                          "name": "question",
                          "text": "Yes",
                          "style": "good",
                          "type": "button",
                          "value": "yes"
                      },
                      {
                          "name": "question",
                          "text": "Nope",
                          "style": "good",
                          "type": "button",
                          "value": "no"
                      }
                  ]
              }
          ])
      }))
  </code></pre>