code: func (ks *KeyStore) ImportECDSAKey(key []byte, passphrase string) (account *Account, _ error) {
  	privkey, err := crypto.ToECDSA(common.CopyBytes(key))
  	if err != nil {
  		return nil, err
  	}
  	acc, err := ks.keystore.ImportECDSA(privkey, passphrase)
  	if err != nil {
  		return nil, err
  	}
  	return &Account{acc}, nil
  }
docs: // ImportECDSAKey stores the given encrypted JSON key into the key directory.