Modify only draft or legacy policies

        Published policies cannot be modified
        :raises: OperationNotSupportedOnPublishedPolicy

def _modify(self, **patch):
        '''Modify only draft or legacy policies

        Published policies cannot be modified
        :raises: OperationNotSupportedOnPublishedPolicy
        '''

        legacy = patch.pop('legacy', False)
        tmos_ver = self._meta_data['bigip']._meta_data['tmos_version']
        self._filter_version_specific_options(tmos_ver, **patch)
        if 'Drafts' not in self._meta_data['uri'] and \
                LooseVersion(tmos_ver) >= LooseVersion('12.1.0') and \
                not legacy:
            msg = 'Modify operation not allowed on a published policy.'
            raise OperationNotSupportedOnPublishedPolicy(msg)
        super(Policy, self)._modify(**patch)