def add_slivers(self, hostnames, attributes=[], sliver_urn=None, append=False):
        # add slice name to network tag
        network_tags = self.xml.xpath('//network')
        if network_tags:
            network_tag = network_tags[0]
            network_tag.set('slice', urn_to_hrn(sliver_urn)[0])

        # add slivers
        sliver = {'name':sliver_urn,
                  'pl_tags': attributes}
        for hostname in hostnames:
            if sliver_urn:
                sliver['name'] = sliver_urn
            node_elems = self.get_nodes({'component_id': hostname % '*%s*'})
            if not node_elems:
                continue
            node_elem = node_elems[0]
            SFAv1Sliver.add_slivers(node_elem.element, sliver)

        # remove all nodes without slivers
        if not append:
            for node_elem in self.get_nodes():
                if not node_elem['slivers']:
                    parent = node_elem.element.getparent()
                    parent.remove(node_elem.element)
dataset/ETHPy150Open fp7-ofelia/ocf/optin_manager/src/python/openflow/optin_manager/sfa/rspecs/.oldversions/sfav1.py/SFAv1.add_slivers/swapped operands of `%`