'Resolves an address.
The ``host`` argument is a string which may be a hostname or a
literal IP address.
Returns a `.Future` whose result is a list of (family,
address) pairs, where address is a tuple suitable to pass to
`socket.connect <socket.socket.connect>` (i.e. a ``(host,
port)`` pair for IPv4; additional fields may be present for
IPv6). If a ``callback`` is passed, it will be run with the
result as an argument when it is complete.
:raises IOError: if the address cannot be resolved.
.. versionchanged:: 4.4
Standardized all implementations to raise `IOError`.'

def resolve(self, host, port, family=socket.AF_UNSPEC, callback=None):

    raise NotImplementedError()
