how do I output a checkbox TV into a UL LI list format

<ul>
<li id="key0">1</li>
<li id="key1">2</li>
<li id="key2">5</li>
</ul>

$output = '';
$tv = $modx->getObject('modTemplateVar',array('name'=>"Facilities"));
// retreives the full array key->value of the TV
$options = explode('||',$tv->get('elements'));
$id = $modx->resource->get('id');
$page = $modx->getObject('modResource', $id);
$tv = $page->getTVValue('Facilities');
// outputs into an array only the keys (checkboxes that are selected only against that document)
$tvarray = explode(',', $tv);
// loops through the array which only contains each of our selected checkboxes
foreach($tvarray AS $option) {
// loops and checks if the key against the full list in $otions exists, if it does exist, appends to $output
if(isset($options[$option])) {
$value = $options[$option];
$output .= "<li>".$value."</li>";
}
}
// the end result, only showing values of the checkbox that has been selected against that document
return $output;

Rooms with En Suite==<li>Rooms with a Suite</li>||Heated Indoor Swimming Pool==<li>Heated Indoor Swimming Pool</li>||Sauna==<li>Sauna</li>||Exercise Studio==<li>Exercise Studio</li>||Treatment Room==<li>Treatment Room</li>||Outdoor Swimming Pool==<li>Outdoor Swimming Pool</li>

<ul>[[*Facilities]]</ul>