[Mediawiki-l] How best to set up hooks in an extension function ?

I thought I had read somewhere that it was not a good idea to set function hooks inside of a class in this way. what follows is just one of many examples out there:

$wgExtensionFunctions[] = 'wfSetupCSS'

function wfSetupCSS() { global $wgCSS; $wgCSS = new CSS(); }

class CSS {

function CSS() { global $wgParser, $wgCSSMagic; $wgParser->setFunctionHook($wgCSSMagic, array($this, 'magicCss')); }

Any other suggestions on how to implement this type of functionality. Would it be better not to instantiate the CSS class and just use a static class with a function to set the hook like this:

$wgExtensionFunctions[] = 'CSS::SetupCSS'

Where SetupCSS was a static function to set the hook.

Sorry if the question appears a bit dumb but I'm interested to hear what the more experienced guys think.

Thanks,

Richard