The subnets which join to make the current subnet.
In the case that self contains only one IP
(self._prefixlen == 32 for IPv4 or self._prefixlen == 128
for IPv6), yield an iterator with just ourself.
Args:
prefixlen_diff: An integer, the amount the prefix length
should be increased by. This should not be set if
new_prefix is also set.
new_prefix: The desired new prefix length. This must be a
larger number (smaller prefix) than the existing prefix.
This should not be set if prefixlen_diff is also set.
Returns:
An iterator of IPv(4|6) objects.
Raises:
ValueError: The prefixlen_diff is too small or too large.
OR
prefixlen_diff and new_prefix are both set or new_prefix
is a smaller number than the current prefix (smaller
number means a larger network)