code: public function get($id, $default = NULL) {
          $data = \apcu_fetch($this->_sanitize_id($id), $success);
  
          return $success ? $data : $default;
      }
docs: Retrieve a cached value entry by id.
  
  // Retrieve cache entry from apc group
  $data = Cache::instance('apc')->get('foo');
  
  // Retrieve cache entry from apc group and return 'bar' if miss
  $data = Cache::instance('apc')->get('foo', 'bar');
  
  @param   string $id id of cache to entry
  @param   string $default default value to return if cache miss
  @return  mixed
  @throws  CacheException