Delete all attachments attached to specified custom posts (card in this case) [Wordpress]

delete_cpt_attachments.php

function delete_cpt_attachments(){
	$attachments = get_posts( array(
	'post_type' => 'attachment',						
	'numberposts' =>-1,	 	  								
		));									
		if ($attachments) {		 		
			foreach ($attachments as $attachment){
	  	$parent_id = $attachment->post_parent;					
				if ( 'card' == get_post_type($parent_id) ) {
					$attachmentID = $attachment->ID;							
					$attachment_path = get_attached_file( $attachmentID); 					
					//Delete attachment from database only, not file
					$delete_attachment = wp_delete_attachment($attachmentID, true);
					//Delete attachment file from disk
					$delete_file = unlink($attachment_path);
				}				
			}
		}					
}