def __init__(self, board_id, list_id, api_key, token=None, **kwargs):
        self.board_id = board_id
        self.list_id = list_id
        self.api_key = api_key
        # assume empty string '' as None
        self.token = token or None

        self.validate()

        self._client = TrelloClient(api_key=self.api_key, token=self.token)
        self._list = self._client.get_board(self.board_id).get_list(self.list_id)
Validate inputs and connect to Trello API.
dataset/ETHPy150Open StackStorm/st2contrib/packs/trello/sensors/list_actions_sensor.py/TrelloList.__init__