diff --git a/include/generic/Singleton.php b/include/generic/Singleton.php
index 77a6fcb..4f40fef 100644
--- a/include/generic/Singleton.php
+++ b/include/generic/Singleton.php
@@ -1,58 +1,59 @@
 <?php
 # Boz-MW - Another MediaWiki API handler in PHP
 # Copyright (C) 2017, 2018, 2019 Valerio Bozzolan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 # generic stuff
 namespace generic;
 
 /**
  * A singleton gives an #instance() method
  */
 trait Singleton {
 
 	/**
 	 * Get an instance of this class
 	 *
 	 * @return self
 	 */
 	public static function instance() {
 		static $instance;
 		if( ! $instance ) {
 			$instance = static::create();
 		}
 		return $instance;
 	}
 
 	/**
 	 * Function to be overrided to create an instance of this class
 	 *
 	 * @return self
 	 */
 	protected static function create() {
 		return new static();
 	}
 
 	/**
-	 * Throw an usage error
-	 */
-	protected static function throwSingletonUsage() {
+  * Throw an usage error
+  * @return never
+  */
+ protected static function throwSingletonUsage() {
 		throw new \Exception( sprintf(
 			'wrong singleton usage, you must call %s::instance()',
 			static::class
 		) );
 	}
 
 }