public function submitForm(array &$form, FormStateInterface $form_state) {
$embedded_form = $form['embedded_entity_form'];
$this->entity = $embedded_form['#entity'];
$form_display = EntityFormDisplay::collectRenderDisplay($this->entity, 'default');
$complete_form_state = $form_state instanceof SubformStateInterface ? $form_state
->getCompleteFormState() : $form_state;
$form_display
->extractFormValues($this->entity, $embedded_form, $complete_form_state);
$this->entity
->save();
}