Custom Rules do not fire unless fields filled in

I am trying to write a custom rule which checks that one or both of these fields have been filled in. The problem is, that if they are both empty, the rule (rule function) never gets called / triggered. If I fill one field it does verify. How do I get this rule to fire if the fields are empty?


[[‘BillingPhoneNumber’, ‘BillingCellPhoneNumber’], ‘phonesVerify’],

[‘BillingPhoneNumber, BillingCellPhoneNumber’], ‘phonesVerify’],

public function phonesVerify($attribute,$params)


	if (!$this->BillingCellPhoneNumber || !$this->BillingPhoneNumber) {

      	// adding error for attribute "phone1" ONLY

      	$this->addError($attribute, 'Phone is required.');		



Solved the problem.

[[‘BillingPhoneNumber’, ‘BillingCellPhoneNumber’], ‘phonesVerify’, ‘skipOnEmpty’=>false],