public function emailOutputTo($addresses)
{
if (is_null($this->_output) || $this->_output == $this->getDefaultOutput()) {
throw new InvalidCallException("Must direct output to a file in order to e-mail results.");
}
$addresses = is_array($addresses) ? $addresses : func_get_args();
return $this->then(function (Application $app) use($addresses) {
$this->emailOutput($app->mailer, $addresses);
});
}