title: Replying to a Thread using Slack Python Webhook API
body: <p>I'm creating a Python script to send messages to a slack channel. The message itself gets delivered fine, however when I try to start a thread and send replies to the thread, I am unable to get it working. The thread replies appear as a new parent message.</p>
  
  <p>I'm using the slack-python-webhook module found at <a href="https://github.com/satoshi03/slack-python-webhook" rel="nofollow noreferrer">https://github.com/satoshi03/slack-python-webhook</a></p>
  
  <pre><code>import slackweb
  import json
  slack = slackweb.Slack(
      url="https://hooks.slack.com/services/XXXX/XXXX/XXXXXX")
  
  
  attachment = [{"text": "This is TEXT",
                "ts": "1564629129"
                }]
  
  
  print(json.dumps(attachment))
  slack.notify(attachments=attachment)
  
  attachment = [{"text": "This is Thread REPLY",
                "thread_ts": "1564629129",
                "thread_ts": "1564629130"
                }]
  
  print(json.dumps(attachment))
  slack.notify(attachments=attachment)
  </code></pre>
  
  <p>I'd like to know what needs to be changed on the above code snippet so the second message will appear as a thread reply.</p>