Make _adverts_account checked by default

Hi,

I am trying to have the account checkbox checked by default.

I tried this, but that’s not working. Is there a way to make it work?

add_filter( "adverts_form_load", "customize_adverts_add", 10, 2 );

function customize_adverts_add( $form ) {
  if( $form['name'] != "advert" ) {
    return $form;
  }

  foreach( $form["field"] as $key => $field ) {
    if( $field["name"] == "_adverts_account" ) {
       $form["field"][$key]["attr"] = array( 'checked' => 'checked' );  
    }
  }

  return $form;
}

Thank you!