code: func (b *Builder) LabelSelectorParam(s string) *Builder {
  	selector := strings.TrimSpace(s)
  	if len(selector) == 0 {
  		return b
  	}
  	if b.selectAll {
  		b.errs = append(b.errs, fmt.Errorf("found non-empty label selector %q with previously set 'all' parameter. ", s))
  		return b
  	}
  	return b.LabelSelector(selector)
  }
docs: // LabelSelectorParam defines a selector that should be applied to the object types to load.
  // This will not affect files loaded from disk or URL. If the parameter is empty it is
  // a no-op - to select all resources invoke `b.LabelSelector(labels.Everything.String)`.