public function isSnippetLanguageIncluded($obj) {
        if($obj instanceof SnippetLanguage) {
            if($this->_cache_language_ids===null) {
                $this->populateLanguageIDs();
            }
            
            return (isset($this->_cache_language_ids[$obj->ID]) && $this->_cache_language_ids[$obj->ID]);
        }else if($obj instanceof Snippet) {
            if($this->_cache_snippet_ids===null) {
                $this->populateSnippetIDs();
            }
            
            return (isset($this->_cache_snippet_ids[$obj->ID]) && $this->_cache_snippet_ids[$obj->ID]);
        }else if($obj instanceof SnippetFolder) {
            if($this->_cache_folder_ids===null) {
                $this->populateFolderIDs();
            }
            
            return (isset($this->_cache_folder_ids[$obj->ID]) && $this->_cache_folder_ids[$obj->ID]);
        }
        
        return false;
    }