type ID … func (i ID) String() string { … } // IDFromString attempts to create an ID from a base-16 string. func IDFromString(s string) (ID, error) { … } type IDSlice … func (p IDSlice) Len() int { … } func (p IDSlice) Less(i, j int) bool { … } func (p IDSlice) Swap(i, j int) { … }