code: def __init__(self, token, channel: str, to_user: str) -> None:
      self._client = slack_sdk.WebClient(token=token)
      self._channel_id = self._get_channel_id(channel)
      self._to_user = (
          to_user
          if to_user == "" or to_user.startswith("@")
          else "@" + to_user
      )
  
file_path: gokart/gokart/slack/slack_api.py
imports: from logging import getLogger
  import slack_sdk
label_desc: Use image node_id 1 to create a new SlackAPI object from inherited base classes: object with example: obj = SlackAPI(token, channel, to_user)