:param dl_description : a DistributionList specifying either :
                   - id:   the dl_list_id
                   - dl_description: the name of the list
        :param attrs  : a dictionary of attributes to set ({key:value,...})

def modify_distribution_list(self, dl_description, attrs):
        """
        :param dl_description : a DistributionList specifying either :
                   - id:   the dl_list_id
                   - dl_description: the name of the list
        :param attrs  : a dictionary of attributes to set ({key:value,...})
        """
        attrs = [{'n': k, '_content': v} for k, v in attrs.items()]
        self.request('ModifyDistributionList', {
            'id': self._get_or_fetch_id(dl_description,
                                        self.get_distribution_list),
            'a': attrs
        })