code: func (s *NestedSort) Source() (interface{}, error) {
  	source := make(map[string]interface{})
  
  	if s.path != "" {
  		source["path"] = s.path
  	}
  	if s.filter != nil {
  		src, err := s.filter.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["filter"] = src
  	}
  	if s.nestedSort != nil {
  		src, err := s.nestedSort.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["nested"] = src
  	}
  
  	return source, nil
  }
docs: // Source returns the JSON-serializable data.