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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def get_participants(self, force_update=False) -> list: """ get all participants |methcoro| Args: force_update (default=False):
 True to force an update to the Challonge API Returns: list[Participant]: Raises: APIException """

        if force_update or self.participants is None:
            res = await self.connection('GET', 'tournaments/{}/participants'.format(self._id))
            self._refresh_participants_from_json(res)
        return self.participants or []