code: func (k *Keyring) installKeys(keys [][]byte, primaryKey []byte) {
  	k.l.Lock()
  	defer k.l.Unlock()
  
  	newKeys := [][]byte{primaryKey}
  	for _, key := range keys {
  		if !bytes.Equal(key, primaryKey) {
  			newKeys = append(newKeys, key)
  		}
  	}
  	k.keys = newKeys
  }
docs: // installKeys will take out a lock on the keyring, and replace the keys with a
  // new set of keys. The key indicated by primaryKey will be installed as the new
  // primary key.