Test item count in the XML response after converting to JSON

Question

I have the following XML output that has two packages in the items block. I want to write a test to check that the response item block has package count 2.

Wrote below test using length function, it works fine when executing the request as an individual. But if I run this test in the postman runner or newman it gets failed saying length is undefined.

Response :

<PackageCollection xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://api.blackbay.com/v2">
    <TotalCount>2</TotalCount>
    <PreviousPage i:nil="true" />
    <NextPage i:nil="true" />
    <Items>
        <Package>
            <Id>18665bd4-2ed9-4261-acd0-fb36746943ba</Id>
            <Barcode>2611508 5016400487671202</Barcode>
            <SpecialInstructions i:nil="true" />
            <Size i:nil="true" />
            <Rules />
        </Package>
        <Package>
            <Id>137bd10e-ee15-4d40-8267-fe098b6a9db7</Id>
            <Barcode>2611508 5016400487671201</Barcode>
            <SpecialInstructions i:nil="true" />
            <Size i:nil="true" />
            <Rules />
        </Package>
    </Items>
</PackageCollection>

Test script:

pm.test("Check response code", function () {
    if (pm.response.to.have.status(200)) {


        pm.test("get Package count", function () {
            const responseJson = xml2Json(pm.response.text());
            const length = responseJson.PackageCollection.Items.Package.length;
            console.log(length);
            pm.expect(length).to.eql(2); 
        });
    }
});

This is responseJson :

Appreciate your help.

Thank you.