// services can be more properly injected.
$allowed_fids = \Drupal::service('session')->get('anonymous_allowed_file_ids', []);
if (!empty($allowed_fids[$entity->id()])) {
// services can be more properly injected.
$allowed_fids = \Drupal::service('session')->get('anonymous_allowed_file_ids', []);
if (!empty($allowed_fids[$entity->id()])) {