code: def setup_method(self):
      self.default_op_kwargs = {
          "slack_webhook_conn_id": "test_conn_id",
          "channel": None,
          "username": None,
          "icon_emoji": None,
          "icon_url": None,
      }
  
file_path: airflow/tests/providers/slack/operators/test_slack_webhook.py
imports: from __future__ import annotations
  from unittest import mock
  import pytest
  from airflow.providers.slack.operators.slack_webhook import SlackWebhookOperator
label_desc: Use image node_id 1 for calling the TestSlackWebhookOperator obj's underlying member method code with example usage: obj.setup_method() without return types