Overrides \Drupal\block\BlockBase::blockSubmit().
Overrides BlockBase::blockSubmit
public function blockSubmit($form, &$form_state) {
$this->configuration['seconds_online'] = $form_state['values']['user_block_seconds_online'];
$this->configuration['max_list_count'] = $form_state['values']['user_block_max_list_count'];
}