code: def test_0_check_connection(self):
      assert self.handler.check_connection()
  
imports: from mindsdb.integrations.handlers.slack_handler import SlackHandler
  import unittest
  from unittest.mock import patch
label_desc: Use image node_id 2 for calling the SlackHandlerTest obj's underlying member method code with example usage: obj.test_0_check_connection() without return types