function verifyCreditSignature(
    DataTypes.Credit memory credit,
    address signer,
    uint8 v,
    bytes32 r,
    bytes32 s
) private view returns (bool) {
    return
        SignatureChecker.verify(
            hashCredit(credit),
            signer,
            v,
            r,
            s,
            getDomainSeparator()
        );
}
struct Credit {
    address token;
    uint256 amount;
    bytes orderId;
    uint8 v;
    bytes32 r;
    bytes32 s;
}
