Take an IP string/int and return an object of the correct type.
Args:
address: A string or integer, the IP address. Either IPv4 or
IPv6 addresses may be supplied; integers less than 2**32 will
be considered to be IPv4 by default.
Returns:
An IPv4Interface or IPv6Interface object.
Raises:
ValueError: if the string passed isn't either a v4 or a v6
address.
Notes:
The IPv?Interface classes describe an Address on a particular
Network, so they're basically a combination of both the Address
and Network classes.