var erc20Bool ERC20Bool
err = e.ABI.UnpackIntoInterface(&erc20Bool, "transfer", resp.Ret)
if err != nil {
    return balanceIncrease, nil, err
}
func (arguments Arguments) Unpack(data []byte) ([]interface{}, error) {
    if len(data) == 0 {
        if len(arguments.NonIndexed()) != 0 {
            return nil, errors.New("abi: attempting to unmarshall an empty string while arguments are expected")
        }
        return make([]interface{}, 0), nil
    }
    return arguments.UnpackValues(data)
}
func (e erc20Calls) Transfer(
    contract, from, to gethcommon.Address, amount *big.Int,
    ctx sdk.Context,
) (balanceIncrease *big.Int, resp *evm.MsgEthereumTxResponse, err error) {
    recipientBalanceBefore, err := e.BalanceOf(contract, to, ctx)
    if err != nil {
        return balanceIncrease, nil, errors.Wrap(err, "failed to retrieve recipient balance")
    }

    resp, err = e.CallContract(ctx, e.ABI, from, &contract, true, Erc20GasLimitExecute, "transfer", to, amount)
    if err != nil {
        return balanceIncrease, nil, err
    }

    // If there's return data, try to unpack it
    if len(resp.Ret) > 0 {
        var erc20Bool ERC20Bool
        if err := e.ABI.UnpackIntoInterface(&erc20Bool, "transfer", resp.Ret); err != nil {
            return balanceIncrease, nil, err
        }
        if !erc20Bool.Value {
            return balanceIncrease, nil, fmt.Errorf("transfer executed but returned success=false")
        }
    }
    // No return data = transfer didn't revert, consider it successful

    recipientBalanceAfter, err := e.BalanceOf(contract, to, ctx)
    if err != nil {
        return balanceIncrease, nil, errors.Wrap(err, "failed to retrieve recipient balance")
    }

    balanceIncrease = new(big.Int).Sub(recipientBalanceAfter, recipientBalanceBefore)
    if balanceIncrease.Sign() <= 0 {
        return balanceIncrease, nil, fmt.Errorf(
            "amount of ERC20 tokens received MUST be positive: the balance of recipient %s would've changed by %v for token %s",
            to.Hex(), balanceIncrease.String(), contract.Hex(),
        )
    }

    return balanceIncrease, resp, nil
}
