public function set_fields()
{
$this->add_field(new acf_fields\text('Text', 'text', '16032500045a'));
$this->add_field(new acf_fields\select('Headline level', 'level', '1603250045b', ['choices' => ['1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5, '6' => 6], 'default_value' => 1, 'allow_null' => 0]));
}