how I can fill field in ACF Group Field in add_post_meta?

This is maybe useful, I tried something, but it doesn’t work.

$values = array('value 1', 'value 2', 'value 3');

Now the code to insert the repeater values:

$repeater_field = 'repeater';
$repeater_key = 'field_5443d4e2dd4e4';
$sub_field = 'sub_field';
$sub_field_key = 'field_5443d4e2dd4e5';

$count = count($values);
if ($count) {
  // the db value stored in the db for a repeater is
  // the number if rows in the repeater
  add_post_meta($post_id, $repeater_field, $count, true);
  add_post_meta($post_id, '_'.$repeater_field, $repeater_key, true);
  for ($i=0; $i<$count; $i++) {
    // the actual field name in the DB is a concatenation of
    // the repeater field name, the index of the current row
    // and the sub field name, with underscores added
    $sub_field_name = $repeater_field.'_'.$i.'_'.$sub_field;
    add_post_meta($post_id, $sub_field_name, $values[$i], false);
    add_post_meta($post_id, '_'.$sub_field_name, $sub_field_key, false);
  }
}

But I need a group. In my case but for the example above, I don’t have array, just single value.