code: func Path(path string, val ...interface{}) Filter {
  	if len(val) > 0 {
  		return Filter{Path: path, Val: val[0]}
  	}
  
  	return Filter{Path: path}
  }
docs: // This creates a new Filter. The path is a dot-delimited path down
  // to the attribute this filter is for. The second value parameter
  // is optional.