class_docstr: Sends a slack notification for a report recipient
code: def _message_template(self, table: str = "") -> str:
      return __(
          """*%(name)s*
  
  %(description)s
  
  <%(url)s|Explore in Superset>
  
  %(table)s
  """,
          name=self._content.name,
          description=self._content.description or "",
          url=self._content.url,
          table=table,
      )
  
imports: import json
  import logging
  from collections.abc import Sequence
  from io import IOBase
  from typing import Union
  import backoff
  import pandas
  from flask import g
  from flask_babel import gettext
  from slack_sdk import WebClient
  from slack_sdk.errors import BotUserAccessError, SlackApiError, SlackClientConfigurationError, SlackClientError, SlackClientNotConnectedError, SlackObjectFormationError, SlackRequestError, SlackTokenRotationError
  from superset import app
  from superset.reports.models import ReportRecipientType
  from superset.reports.notifications.base import BaseNotification
  from superset.reports.notifications.exceptions import NotificationAuthorizationException, NotificationMalformedException, NotificationParamException, NotificationUnprocessableException
  from superset.utils.core import get_email_address_list
  from superset.utils.decorators import statsd_gauge
label_desc: Use image node_id 2 for calling the SlackNotification obj's underlying member method code with example usage: obj._message_template(table) and returns: __