How to use the @0x/types.SignatureType.EIP712 function in @0x/types

const feeRecipientIfExists = _.find(
                this._configs.CHAIN_ID_TO_SETTINGS[chainId].FEE_RECIPIENTS,
                f => f.ADDRESS === feeRecipientAddress,
            );
            if (feeRecipientIfExists === undefined) {
                // This error should never be hit
                throw new Error(
                    `Unexpected error: Found feeRecipientAddress ${feeRecipientAddress} that wasn't specified in config.`,
                );
            }
            const signature = ethUtil.ecsign(approvalHashBuff, Buffer.from(feeRecipientIfExists.PRIVATE_KEY, 'hex'));
            const signatureBuffer = Buffer.concat([
                ethUtil.toBuffer(signature.v),
                signature.r,
                signature.s,
                ethUtil.toBuffer(SignatureType.EIP712),
            ]);
            const approvalSignatureHex = ethUtil.addHexPrefix(signatureBuffer.toString('hex'));
            signatures.push(approvalSignatureHex);
        }

        return {
            signatures,
            expirationTimeSeconds: approvalExpirationTimeSeconds,
        };
    }
} // tslint:disable:max-file-line-count

): Promise {
        const provider = providerUtils.standardizeOrThrow(supportedProvider);
        assert.isETHAddressHex('signerAddress', signerAddress);
        assert.doesConformToSchema('order', order, schemas.orderSchema, [schemas.hexSchema]);
        const web3Wrapper = new Web3Wrapper(provider);
        await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
        const normalizedSignerAddress = signerAddress.toLowerCase();
        const typedData = eip712Utils.createOrderTypedData(order);
        try {
            const signature = await web3Wrapper.signTypedDataAsync(normalizedSignerAddress, typedData);
            const ecSignatureRSV = parseSignatureHexAsRSV(signature);
            const signatureBuffer = Buffer.concat([
                ethUtil.toBuffer(ecSignatureRSV.v),
                ethUtil.toBuffer(ecSignatureRSV.r),
                ethUtil.toBuffer(ecSignatureRSV.s),
                ethUtil.toBuffer(SignatureType.EIP712),
            ]);
            const signatureHex = `0x${signatureBuffer.toString('hex')}`;
            return {
                ...order,
                signature: signatureHex,
            };
        } catch (err) {
            // Detect if Metamask to transition users to the MetamaskSubprovider
            if ((provider as any).isMetaMask) {
                throw new Error(TypedDataError.InvalidMetamaskSigner);
            } else {
                throw err;
            }
        }
    },
    /**

): Promise {
        const provider = providerUtils.standardizeOrThrow(supportedProvider);
        assert.isETHAddressHex('signerAddress', signerAddress);
        assert.doesConformToSchema('transaction', transaction, schemas.zeroExTransactionSchema, [schemas.hexSchema]);
        const web3Wrapper = new Web3Wrapper(provider);
        await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
        const normalizedSignerAddress = signerAddress.toLowerCase();
        const typedData = eip712Utils.createZeroExTransactionTypedData(transaction);
        try {
            const signature = await web3Wrapper.signTypedDataAsync(normalizedSignerAddress, typedData);
            const ecSignatureRSV = parseSignatureHexAsRSV(signature);
            const signatureBuffer = Buffer.concat([
                ethUtil.toBuffer(ecSignatureRSV.v),
                ethUtil.toBuffer(ecSignatureRSV.r),
                ethUtil.toBuffer(ecSignatureRSV.s),
                ethUtil.toBuffer(SignatureType.EIP712),
            ]);
            const signatureHex = `0x${signatureBuffer.toString('hex')}`;
            return {
                ...transaction,
                signature: signatureHex,
            };
        } catch (err) {
            // Detect if Metamask to transition users to the MetamaskSubprovider
            if ((provider as any).isMetaMask) {
                throw new Error(TypedDataError.InvalidMetamaskSigner);
            } else {
                throw err;
            }
        }
    },
    /**

private readonly _eip712SignatureAsync = async (address: string, typedData: any): Promise => {
        const signature = await this.props.web3Wrapper.signTypedDataAsync(address, typedData);
        const ecSignatureRSV = this._parseSignatureHexAsRSV(signature);
        const signatureBuffer = Buffer.concat([
            ethUtil.toBuffer(ecSignatureRSV.v),
            ethUtil.toBuffer(ecSignatureRSV.r),
            ethUtil.toBuffer(ecSignatureRSV.s),
            ethUtil.toBuffer(SignatureType.EIP712),
        ]);
        const signatureHex = `0x${signatureBuffer.toString('hex')}`;
        return signatureHex;
    };
    private _parseSignatureHexAsRSV(signatureHex: string): ECSignature {