code: func (u *User) GetPublicKeyByLabel(label string) (publicKey PublicKey, err error) {
  	for _, publicKey = range u.PublicKeys {
  		if publicKey.Label == label {
  			return
  		}
  	}
  	err = errors.New("Could not find PublicKey with label " + label)
  	return
  }
docs: // GetPublicKeyByLabel Gets the public key associated with this label