public function configSet($collection, $key, $value) {
    $value = base64_encode(Yaml::dump($value));

    if ($index = array_search('--format=json', $this->options)) {
      unset($this->options[$index]);
    }
    $this->options[] = '--format=yaml';
    $this->options[] = '-y';

    $pipe = "echo '$value' | base64 --decode |";

    $this->runCommand('config-set', [
      $collection, $key, '-'
    ], $pipe);

    return TRUE;
  }