BaseEventTypeElement::requiredIfSide PHP Method

    public function requiredIfSide($attribute, $params)
    {
        if ($params['side'] == 'left' && $this->eye_id != 2 || $params['side'] == 'right' && $this->eye_id != 1) {
            if ($this->{$attribute} == null) {
                if (!@$params['message']) {
                    $params['message'] = ucfirst($params['side']) . ' {attribute} cannot be blank.';
                }
                $params['{attribute}'] = $this->getAttributeLabel($attribute);
                $this->addError($attribute, strtr($params['message'], $params));
            }
        }
    }