code: def test_initialization_with_invalid_token(self, patch):
      def _conversations_list(params={}):
          return _slack_response(
              token="invalid",
              data={"ok": False, "error": "error_reason"},
          )
  
      mock_client = MagicMock()
      mock_client.conversations_list = MagicMock(
          side_effect=_conversations_list
      )
      patch.return_value = mock_client
  
      with LogCapture() as log:
          gokart.slack.SlackAPI(
              token="invalid", channel="test", to_user="test user"
          )
          log.check(
              (
                  "gokart.slack.slack_api",
                  "WARNING",
                  "The job will start without slack notification: Channel test is not found in public channels.",
              )
          )
  
file_path: gokart/test/slack/test_slack_api.py
imports: import unittest
  from logging import getLogger
  from unittest import mock
  from unittest.mock import MagicMock
  from slack_sdk import WebClient
  from slack_sdk.web.slack_response import SlackResponse
  from testfixtures import LogCapture
  import gokart.slack
label_desc: Use image node_id 1 for calling the TestSlackAPI obj's underlying member method code with example usage: obj.test_initialization_with_invalid_token(patch) and returns: _slack_response