Simple Question: reading TV values from within a Snippet

$val = $modx->resource->getTVValue('nameOfTV');

$val = $modx->resource->getTVValue(##);

$tv = $modx->getObject('modTemplateVar',##);
$val = $tv->getValue($id); // (Id of the resource, not the TV

$id = $modx->resourceIdentifier; // gets the current page id
$Resource = $modx->getObject('modResource', $id);
$value = $Resource->getTVValue('my_TV');

$value = $modx->resource->getTVValue('my_TV');