code: func (ns *Namespace) PostCSS(args ...interface{}) (resource.Resource, error) {
  	r, m, err := ns.resolveArgs(args)
  	if err != nil {
  		return nil, err
  	}
  	var options postcss.Options
  	if m != nil {
  		options, err = postcss.DecodeOptions(m)
  		if err != nil {
  			return nil, err
  		}
  	}
  
  	return ns.postcssClient.Process(r, options)
  }
docs: // PostCSS processes the given Resource with PostCSS