Is form field validation still working

I have put in the following custom validation rule in the script but it never gets called.
What am I doing wrong here.

window.ub.form.customValidators.addressValidator = {
isValid: function(value) {
return value !== ‘30022’;
},
message: ‘Your entry is invalid’,
};

window.ub.form.validationRules.postal_code.addressValidator = true;