private function addPreviousToOutput(array $entry, string $output): array
    {
        if (isset($entry['previous']) && \count($entry['previous']) !== 0) {
            foreach ((array) $entry['previous'] as $key => $value) {
                if (\is_string($value)) {
                    $output .= '#| ' . $key . ' ' . $this->cleanExport($value) . $this->eol;
                } elseif (\is_array($value) && \count($value) > 0) {
                    foreach ($value as $line) {
                        $output .= '#| ' . $key . ' ' . $this->cleanExport($line) . $this->eol;
                    }
                }
            }
        }

        return [$entry, $output];
    }