Gravity_Forms::delete_signup

public static function delete_signup( $key ) {
		
	// get signup from $key ##
  	$signup = GFSignup::get( $key );
		
	// return error, if nothing found ##
  	if( is_wp_error( $signup ) ) {
			
    		return $signup;
			
	}

	// grab user ID ##
  	$user_id = username_exists( $signup->user_login );
		
  	if ( $user_id ){
			
		// log ##
		GFUser::log_debug( "Failed to delete signup for username: {$signup->user_login} - entry: {$signup->lead["id"]}" );
			
        	// username already exists, they must have been activated in another way ##
        	return new WP_Error( 'user_already_exists', __( 'That username is already activated.' ), $signup );
			
        } else {
			
      		// log ##
      		GFUser::log_debug( "Delete signup for username: {$signup->user_login} - entry: {$signup->lead["id"]}" );
      	
      		// hook - send all signup data Array ##
      		do_action( 'gform_delete_user', $signup );
      	
      		// grab database object ##
      		global $wpdb;
	
	      	// delete row from signups table ##
        	return $wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->signups WHERE activation_key = %s", $key ) );
			
      	}
		
}