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