code: protected function escape(array $options)
      {
          $results = [];
          foreach ($options as $key => $value) {
              if (!in_array($key, $this->safe)) {
                  $results[$key] = escapeshellarg($value);
              } else {
                  $results[$key] = $value;
              }
          }
  
          return $results;
      }
docs: Escapes the set of option values.
  
  @param array A set of key/value options.
  @return array The sanitized set of key/value options.