Format of blank imported CSV values

What format are blank entries imported from a CSV file as? I’ve tried declaring them as undefined and as ’ ’ and I can’t seem to get the IF part of my statement below to trigger. My goal is to skip any test validations if the variable MobilityCTN is undefined in the imported CSV file.

if (typeof(pm.environment.get(‘MobilityCTN’)) === ‘undefined’) {
//No tests scripts to verify. Move to the next request.
}
else {
pm.test(“Status code is 200”, function () {
pm.response.to.have.status(200);
});
pm.test(“Response contains success.”, function () {
pm.expect(pm.response.text()).to.include(“SUCCESS”);
});
}

Thanks!