static function pf_toplevelpage( &$parser /* , $title = null */ ) {		
		$t = self::newTitleObject( $parser, func_get_args() );
		if( $t === null ) {
			return ''; // invalid title given
		}
		
		//get all parents because the toplevel is the highest existing parent:
		$parentpages = SubpageInfo::getAncestorPages( $t );
		
		if( ! empty( $parentpages ) ) {
			return wfEscapeWikiText( $parentpages[0]->getPrefixedText() );
		}
		else {
			////no parent! The page itself is the top level:
			return wfEscapeWikiText( $t->getPrefixedText() );
		}
	}
	/**
	 * Delivers the subpage level of a given Page.
	 * 
	 * @param Title $page Page to get the level from.
	 * 
	 * @return Title Result The Level the given page has. Level 0 means the given page is no subpage at all.
	 */	
	static function getSubpageLevel( Title $page ) {		
		$ancestors = SubpageInfo::getAncestorPages( $page );
		
		if( ! empty( $ancestors ) ) {					
			return count ($ancestors );
		}
		else //no parent! The page itself is the top level:
			return 0;
	}