def port_uris_prop(self):
        """
        :term:`string`: Name of adapter property that specifies the adapter
        port URIs, or the empty string ('') for adapters without ports.

        For example, 'network-port-uris' for a network adapter.
        """
        if self._port_uris_prop is None:
            family = self.get_property('adapter-family')
            try:
                self._port_uris_prop = self.port_uris_prop_by_family[family]
            except KeyError:
                self._port_uris_prop = ''
        return self._port_uris_prop