public function getRulesWithSourceSpecification()
    {
        $rulesWithSource = [];

        foreach ($this->attributeRules as $name => $rules) {
            $rulesWithSource[$name] = array_filter(
                $rules,
                function ($rule) {
                    return isset($rule['source']);
                }
            );
        }

        return array_filter($rulesWithSource);
    }