Create the <relations> etree element of an RS3 file.
        This represents all relation types (both 'rst' and 'multinuc').

        Example relation:
            <rel name="circumstance" type="rst" />

def gen_relations(self):
        """Create the <relations> etree element of an RS3 file.
        This represents all relation types (both 'rst' and 'multinuc').

        Example relation:
            <rel name="circumstance" type="rst" />
        """
        relations_elem = E('relations')
        for relname in sorted(self.relations):
            relations_elem.append(
                E('rel', OrderedDict([('name', relname), ('type', self.relations[relname])])))
        return relations_elem