Slack Web API未在松弛消息中发布表情符号

Question

payload ={'channel': '#test', 'username': 'slack_username', 'attachments': [{'color': '#ff0000', 'text': 'Passed=1 Failed=0 Skipped=0 Error=0 XFailed=0 XPassed=0', 'mrkdwn_in': ['text', 'pretext']}], 'icon_emoji': ':hugging_face:', 'icon_url': ':hugging_face:'}

requests.post('<slack-hook>', data=json.dumps(payload), timeout=5).json()

此api成功 但表情符号和用户名未发布到松弛消息中