How to use the eth-sig-util.recoverTypedSignature_v4 function in eth-sig-util

it('returns the expected value', async () => {
      const typedData = {"data":{"types":{"EIP712Domain":[{"name":"name","type":"string"},{"name":"version","type":"string"},{"name":"chainId","type":"uint256"},{"name":"verifyingContract","type":"address"}],"Person":[{"name":"name","type":"string"},{"name":"wallets","type":"address[]"}],"Mail":[{"name":"from","type":"Person"},{"name":"to","type":"Person[]"},{"name":"contents","type":"string"}],"Group":[{"name":"name","type":"string"},{"name":"members","type":"Person[]"}]},"domain":{"name":"Ether Mail","version":"1","chainId":1,"verifyingContract":"0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"},"primaryType":"Mail","message":{"from":{"name":"Cow","wallets":["0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826","0xDeaDbeefdEAdbeefdEadbEEFdeadbeEFdEaDbeeF"]},"to":[{"name":"Bob","wallets":["0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB","0xB0BdaBea57B0BDABeA57b0bdABEA57b0BDabEa57","0xB0B0b0b0b0b0B000000000000000000000000000"]}],"contents":"Hello, Bob!"}}}

      await keyring.deserialize([privKeyHex])

      const addresses = await keyring.getAccounts()
      const address = addresses[0]

      const sig = await keyring.signTypedData_v4(address, typedData.data)
      assert.equal(sig, expectedSig, 'verified signature')
      const signedData = Object.create(typedData)
      signedData.sig = sig
      const restored = sigUtil.recoverTypedSignature_v4(signedData)
      assert.equal(restored, address, 'recovered address')
    })
  })

}, function (err, result) {
    if (err) return console.dir(err)
    if (result.error) {
      alert(result.error.message)
    }
    if (result.error) return console.error('ERROR', result)
    console.log('TYPED SIGNED:' + JSON.stringify(result.result))

    const recovered = sigUtil.recoverTypedSignature_v4({ data: JSON.parse(msgParams), sig: result.result })

    if (ethUtil.toChecksumAddress(recovered) === ethUtil.toChecksumAddress(from)) {
      alert('Successfully recovered signer as ' + from)
    } else {
      alert('Failed to verify signer when comparing ' + result + ' to ' + from)
    }

  })