How to detect the region of a block programatically I need to create a custom submit handler when blocks that are assigned to a certain region are saved (whether an existing or a new block)

I am using :

function MY_MODULE_NAME_form_alter(&amp;$form, $form_state, $form_id) {
  if ($form['#id'] == 'block-admin-configure'){

    //If the block being saved is in region "Header" then do something
  }


Can someone tell me what to replace my commented line with please ?
You can implement hook_block_save($delta = '', $edit = array()) to execute your custom code.