Validate for each subform

Hello,

I have used subform module to emebed subfrom with some option with required field for example. When I submit a wrapper form error message for this required field does not show.

My code for subform

$form = array(
      '#type' => 'subform',
      '#subform_id' => 'my_subform',
      '#subform_arguments' => array($nid),
      '#required' => TRUE,
);