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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:
 def channels_add_owner(self, room_id, user_id=None, username=None, **kwargs):
 """Gives the role of owner for a user in the current channel."""

        if user_id:
            return self.__call_api_post('channels.addOwner', roomId=room_id, userId=user_id, kwargs=kwargs)
        elif username:
            return self.__call_api_post('channels.addOwner', roomId=room_id, username=username, kwargs=kwargs)
        else:
            raise RocketMissingParamException('userID or username required')