public function addError($message, $severity = Validator\Rule::ERROR,
        array $indexes = []
    ) {
        $rule = new Validator\Rule(
            $this->entity,
            function () {
                return false;
            },
            $message,
            $this->property,
            $severity,
            $this->child
        );
        $rule->setChildFailed($indexes);
        $this->rules[] = $rule;
        return $this;
    }