trait ObjectToPopulateTrait

trait ObjectToPopulateTrait {
    
    /**
     * Extract the `object_to_populate` field from the context if it exists
     * and is an instance of the provided $class.
     *
     * @param string      $class The class the object should be
     * @param string|null $key   They in which to look for the object to populate.
     *                           Keeps backwards compatibility with `AbstractNormalizer`.
     */
    protected function extractObjectToPopulate(string $class, array $context, ?string $key = null) : ?object {
        $key ??= AbstractNormalizer::OBJECT_TO_POPULATE;
        if (isset($context[$key]) && \is_object($context[$key]) && $context[$key] instanceof $class) {
            return $context[$key];
        }
        return null;
    }

}