def update_list(self, picklist, list_id):
        """UpdateList.
        [Preview API] Updates a list.
        :param :class:`<PickList> <azure.devops.v5_0.work_item_tracking_process.models.PickList>` picklist:
        :param str list_id: The ID of the list
        :rtype: :class:`<PickList> <azure.devops.v5_0.work_item_tracking_process.models.PickList>`
        """
        route_values = {}
        if list_id is not None:
            route_values['listId'] = self._serialize.url('list_id', list_id, 'str')
        content = self._serialize.body(picklist, 'PickList')
        response = self._send(http_method='PUT',
                              location_id='01e15468-e27c-4e20-a974-bd957dcccebc',
                              version='5.0-preview.1',
                              route_values=route_values,
                              content=content)
        return self._deserialize('PickList', response)