def _compact_single_network(self, added_network):
        added_first = added_network.first
        added_last = added_network.last
        added_version = added_network.version

        # Check for supernets and subnets of added_network.
        if added_network._prefixlen == added_network._module.width:
            # This is a single IP address, i.e. /32 for IPv4 or /128 for IPv6.
            # It does not have any subnets, so we only need to check for its
            # potential supernets.
            for potential_supernet in added_network.supernet():
                if potential_supernet in self._cidrs:
                    del self._cidrs[added_network]
                    return
        else:
            # IPNetworks from self._cidrs that are subnets of added_network.
            to_remove = []
            for cidr in self._cidrs:
                if (cidr._module.version != added_version or cidr == added_network):
                    # We found added_network or some network of a different version.
                    continue
                first = cidr.first
                last = cidr.last
                if first >= added_first and last <= added_last:
                    # cidr is a subnet of added_network. Remember to remove it.
                    to_remove.append(cidr)
                elif first <= added_first and last >= added_last:
                    # cidr is a supernet of added_network. Remove added_network.
                    del self._cidrs[added_network]
                    # This IPSet was properly compacted before. Since added_network
                    # is removed now, it must again be properly compacted -> done.
                    assert (not to_remove)
                    return
            for item in to_remove:
                del self._cidrs[item]

        # Check if added_network can be merged with another network.

        # Note that merging can only happen between networks of the same
        # prefixlen. This just leaves 2 candidates: The IPNetworks just before
        # and just after the added_network.
        # This can be reduced to 1 candidate: 10.0.0.0/24 and 10.0.1.0/24 can
        # be merged into into 10.0.0.0/23. But 10.0.1.0/24 and 10.0.2.0/24
        # cannot be merged. With only 1 candidate, we might as well make a
        # dictionary lookup.
        shift_width = added_network._module.width - added_network.prefixlen
        while added_network.prefixlen != 0:
            # figure out if the least significant bit of the network part is 0 or 1.
            the_bit = (added_network._value >> shift_width) & 1
            if the_bit:
                candidate = added_network.previous()
            else:
                candidate = added_network.next()

            if candidate not in self._cidrs:
                # The only possible merge does not work -> merge done
                return
            # Remove added_network&candidate, add merged network.
            del self._cidrs[candidate]
            del self._cidrs[added_network]
            added_network.prefixlen -= 1
            # Be sure that we set the host bits to 0 when we move the prefixlen.
            # Otherwise, adding 255.255.255.255/32 will result in a merged
            # 255.255.255.255/24 network, but we want 255.255.255.0/24.
            shift_width += 1
            added_network._value = (added_network._value >> shift_width) << shift_width
            self._cidrs[added_network] = True
Same as compact(), but assume that added_network is the only change and
dataset/ETHPy150Open drkjam/netaddr/netaddr/ip/sets.py/IPSet._compact_single_network