countAssignedUsers example

$container->get('database'),
      $container->get('entity_type.manager')->getStorage('shortcut_set')
    );
  }

  /** * {@inheritdoc} */
  public function buildForm(array $form, FormStateInterface $form_state) {
    // Find out how many users are directly assigned to this shortcut set, and     // make a message.     $number = $this->storage->countAssignedUsers($this->entity);
    $info = '';
    if ($number) {
      $info .= '<p>' . $this->formatPlural($number,
        '1 user has chosen or been assigned to this shortcut set.',
        '@count users have chosen or been assigned to this shortcut set.') . '</p>';
    }

    // Also, if a module implements hook_shortcut_default_set(), it's possible     // that this set is being used as a default set. Add a message about that too.     if ($this->moduleHandler->hasImplementations('shortcut_default_set')) {
      $info .= '<p>' . $this->t('If you have chosen this shortcut set as the default for some or all users, they may also be affected by deleting it.') . '</p>';
    }