code: func (iamRes *IAMResourceBuilder) Attr(resName string, propName string, delimiter ...string) *IAMResourceBuilder {
  	iamRes.resourceParts = append(iamRes.resourceParts,
  		gocf.GetAtt(resName, propName))
  	for _, eachDelimiter := range delimiter {
  		iamRes.resourceParts = append(iamRes.resourceParts,
  			gocf.String(eachDelimiter))
  	}
  	return iamRes
  }
docs: // Attr inserts a go-cloudformation GetAtt entry