private function syncKeysFromFiles($translationFiles)
    {
        $this->info('Reading translation keys from files...');

        // An array of all translation keys as found in project files.
        $allKeysInFiles = $this->manager->collectFromFiles();

        foreach ($translationFiles as $fileName => $languages) {
            foreach ($languages as $languageKey => $path) {
                $fileContent = $this->manager->getFileContent($path);

                if (isset($allKeysInFiles[$fileName])) {
                    $missingKeys = array_diff($allKeysInFiles[$fileName], array_keys(array_dot($fileContent)));

                    foreach ($missingKeys as $i => $missingKey) {
                        if (Arr::has($fileContent, $missingKey)) {
                            unset($missingKeys[$i]);
                        }
                    }

                    $this->fillMissingKeys($fileName, $missingKeys, $languageKey);
                }
            }
        }
    }