// removal after the retention specified in Make()
func (s smtLedger) Put(key, value string) (result string, err error) {
	b, err := s.tree.Update([][]byte{coerceKeyToHashLen(key)}, [][]byte{coerceToHashLen(value)})
	result = string(b)
	return
}

// Delete removes a key value pair from the ledger, marking it for removal after the retention specified in Make()
func (s smtLedger) Delete(key string) (err error) {