def supernet(self, prefixlen=0):
        if not 0 <= prefixlen <= self._module.width:
            raise ValueError('CIDR prefix /%d invalid for IPv%d!' \
                % (prefixlen, self._module.version))

        supernets = []
        # Use a copy of self as we'll be editing it.
        supernet = self.cidr
        supernet._prefixlen = prefixlen
        while supernet._prefixlen != self._prefixlen:
            supernets.append(supernet.cidr)
            supernet._prefixlen += 1
        return supernets
Provides a list of supernets for this `IPNetwork` object between the
dataset/ETHPy150Open drkjam/netaddr/netaddr/ip/__init__.py/IPNetwork.supernet