class_docstr: A Mattermost communication channel.
class_docstr_tok: ["A","Mattermost","communication","channel","."]
docstr: Send a message to a mattermost channel.
docstr_tok: ["Send","a","message","to","a","mattermost","channel","."]
code: def _post_data_to_channel(self, data: Dict[Text, Any]) -> Response:
      """Send a message to a mattermost channel."""
      headers = {"Authorization": "Bearer " + self.token}
      r = requests.post(
          self.url + "/posts", headers=headers, data=json.dumps(data)
      )
      if not r.status_code == 200:
          logger.error(
              f"Failed to send message to mattermost channel "
              f"{data.get('channel_id')}. Response: {r}"
          )
      return r
  
imports: import json
  import logging
  import requests
  from requests import Response
  from sanic import Blueprint, response
  from sanic.request import Request
  from typing import Text, Dict, Any, List, Callable, Awaitable, Optional
  from rasa.core.channels.channel import UserMessage, OutputChannel, InputChannel
  from sanic.response import HTTPResponse
label_desc: Use image node_id 5 for calling the MattermostBot obj's underlying member method code with example usage: obj._post_data_to_channel(data) and returns: r