func (pk PrivKeyLedgerSecp256k1) ValidateKey() error {
	// getPubKey will return an error if the ledger is not
	pub, err := pk.getPubKey()
	if err != nil {
		return err
	}
	// verify this matches cached address
	if !pub.Equals(pk.CachedPubKey) {
		return fmt.Errorf("cached key does not match retrieved key")
	}
	return nil
}
func (pk PrivKeyLedgerSecp256k1) ValidateKey() error {
	// getPubKey will return an error if the ledger is not
	pub, err := pk.getPubKey()
	if err != nil {
		return err
	}
	// verify this matches cached address
	if !pub.Equals(pk.CachedPubKey) {
		return fmt.Errorf("cached key does not match retrieved key")
	}
	return nil
}
// ValidateKey allows us to verify the sanity of a key
// after loading it from disk