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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 update_notifications(self, on_match_open: bool = None, on_tournament_end: bool = None):
 """ update participants notifications for this tournament |methcoro| Args: on_match_open: Email registered Challonge participants when matches open up for them on_tournament_end: Email registered Challonge participants the results when this tournament ends Raises: APIException """

        params = {}
        if on_match_open is not None:
            params['notify_users_when_matches_open'] = on_match_open
        if on_tournament_end is not None:
            params['notify_users_when_the_tournament_ends'] = on_tournament_end
        assert_or_raise(len(params) > 0, ValueError, 'At least one of the notifications must be given')
        await self.update(**params)