def METHOD_NAME(cls, serverAddress, domain):
    """
    Construct a new L{SecondaryAuthority} from a tuple giving a server
    address and a C{bytes} giving the name of a domain for which this is an
    authority.
    @param serverAddress: A two-tuple, the first element of which is a
        C{str} giving an IP address and the second element of which is a
        C{int} giving a port number.  Together, these define where zone
        transfers will be attempted from.
    @param domain: A C{bytes} giving the domain to transfer.
    @type domain: L{bytes}
    @return: A new instance of L{SecondaryAuthority}.
    """
    primary, port = serverAddress
    secondary = cls(primary, domain)
    secondary._port = port
    return secondary