/**
 * Implements hook_install().
 */
function {{ machine_name }}_install() {
  // Create the styles directory and ensure it's writable.
  $directory = \Drupal::config('system.file')->get('default_scheme') . '://styles';
  \Drupal::service('file_system')->prepareDirectory($directory, FileSystemInterface::CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS);
}