code: func (k *Keyring) RemoveKey(key []byte) error {
  	if bytes.Equal(key, k.keys[0]) {
  		return fmt.Errorf("Removing the primary key is not allowed")
  	}
  	for i, installedKey := range k.keys {
  		if bytes.Equal(key, installedKey) {
  			keys := append(k.keys[:i], k.keys[i+1:]...)
  			k.installKeys(keys, k.keys[0])
  		}
  	}
  	return nil
  }
docs: // RemoveKey drops a key from the keyring. This will return an error if the key
  // requested for removal is currently at position 0 (primary key).