Devise\Pages\PageVersionManager::copyCollectionsFromVersionToVersion PHP Method

    protected function copyCollectionsFromVersionToVersion($oldVersion, $newVersion)
    {
        foreach ($oldVersion->collectionInstances as $oldInstance) {
            $newInstance = $this->CollectionInstance->create(['collection_set_id' => $oldInstance->collection_set_id, 'page_version_id' => $newVersion->id, 'name' => $oldInstance->name, 'sort' => $oldInstance->sort]);
            foreach ($oldInstance->fields as $field) {
                $this->Field->create(["collection_instance_id" => $newInstance->id, "page_version_id" => $newVersion->id, "type" => $field->type, "human_name" => $field->human_name, "key" => $field->key, "json_value" => $field->json_value]);
            }
        }
    }