code: func (r *ResourceDefinition) IterateFileServers(it FileServerIterator) error {
  	sort.Sort(ByFilePath(r.FileServers))
  	for _, f := range r.FileServers {
  		if err := it(f); err != nil {
  			return err
  		}
  	}
  	return nil
  }
docs: // IterateFileServers calls the given iterator passing each resource file server sorted by file
  // path. Iteration stops if an iterator returns an error and in this case IterateFileServers returns
  // that error.