'Specify an aliases(5) file to use for the last specified domain.'

def opt_aliases(self, filename):

    if (self.last_domain is not None):
        if mail.IAliasableDomain.providedBy(self.last_domain):
            aliases = alias.loadAliasFile(self.service.domains, filename)
            self.last_domain.setAliasGroup(aliases)
            self.service.monitor.monitorFile(filename, AliasUpdater(self.service.domains, self.last_domain))
        else:
            raise usage.UsageError(('%s    does    not    support    alias    files' % (self.last_domain.__class__.__name__,)))
    else:
        raise usage.UsageError('Specify    a    domain    before    specifying    aliases')
