code: func (t *Trie) Update(key, value []byte) {
  	if err := t.TryUpdate(key, value); err != nil {
  		log.Error(fmt.Sprintf("Unhandled trie error: %v", err))
  	}
  }
docs: // Update associates key with value in the trie. Subsequent calls to
  // Get will return value. If value has length zero, any existing value
  // is deleted from the trie and calls to Get will return nil.
  //
  // The value bytes must not be modified by the caller while they are
  // stored in the trie.