code: func (w *trezorDriver) SignTx(path accounts.DerivationPath, tx *types.Transaction, chainID *big.Int) (common.Address, *types.Transaction, error) {
  	if w.device == nil {
  		return common.Address{}, nil, accounts.ErrWalletClosed
  	}
  	return w.trezorSign(path, tx, chainID)
  }
docs: // SignTx implements usbwallet.driver, sending the transaction to the Trezor and
  // waiting for the user to confirm or deny the transaction.