diff --git "a/include/class-mw\\WikibaseSite.php" "b/include/class-mw\\WikibaseSite.php"
index 9ec59b6..2cee77c 100644
--- "a/include/class-mw\\WikibaseSite.php"
+++ "b/include/class-mw\\WikibaseSite.php"
@@ -1,108 +1,108 @@
 <?php
-# Boz-MW - Another MediaWiki API handler in PHP
-# Copyright (C) 2017, 2018, 2019, 2020 Valerio Bozzolan
+# boz-mw - Another MediaWiki API handler in PHP
+# Copyright (C) 2017, 2018, 2019, 2020, 2021 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/>.
 
 # MediaWiki
 namespace mw;
 
 /**
  * A site with wikibase enabled
  */
 class WikibaseSite extends Site {
 
 	/**
 	 * Fetch a single Wikidata entity using the wbgetentities API
 	 *
 	 * See:
 	 *   https://www.wikidata.org/w/api.php?action=help&modules=wbgetentities
 	 *
 	 * @param $entity_id string Entity Q-ID
 	 * @param $data array Additional data such as [ 'props' => '..' ]
 	 *   Some available props:
 	 *      aliases, claims, datatype, descriptions, info, labels, sitelinks, sitelinks/urls
 	 * @return wb\DataModel
 	 */
 	public function fetchSingleEntity( $entity_id, $data = [] ) {
 
 		$data = array_replace( [
 			'action' => 'wbgetentities',
 			'ids'    => $entity_id,
 		], $data );
 
 		$entity = $this->fetch( $data );
 		if( ! isset( $entity->entities->{ $entity_id } ) ) {
-			throw new Exception( "$wikidata_item does not exist" );
+			throw new Exception( "$entity_id does not exist" );
 		}
 
 		return $this->createDataModelFromObject( $entity->entities->{ $entity_id } );
 	}
 
 	/**
 	 * Edit a Wikidata entity using the wbeditentity API
 	 *
 	 * You do not need to send the CSRF 'token' and the 'action' parameters.
 	 *
 	 * See:
 	 *   https://www.wikidata.org/w/api.php?action=help&modules=wbeditentity
 	 *
 	 * @param $data array API data request (with some extensions)
 	 * 	Allowed extensions:
 	 * 		summary.pre  Add something before the summary
 	 * 		summary.post Add something after  the summary
 	 * @return mixed
 	 */
 	public function editEntity( $data = [] ) {
 
 		// extends the API arguments adding a 'summary.pre' argument
 		if( isset( $data[ 'summary.pre' ] ) ) {
 			$data[ 'summary' ] = $data[ 'summary.pre' ] . $data[ 'summary' ];
 			unset( $data[ 'summary.pre' ] );
 		}
 
 		// extends the API arguments adding a 'summary.post' argument
 		if( isset( $data[ 'summary.post' ] ) ) {
 			$data[ 'summary' ] .= $data[ 'summary.post' ];
 			unset( $data[ 'summary.post' ] );
 		}
 
 		return $this->post( array_replace( [
 			'action' => 'wbeditentity',
 			'token'  => $this->getToken( \mw\Tokens::CSRF ),
 		], $data ) );
 	}
 
 	/**
 	 * Create an empty Wikibase data model related to this site
 	 *
 	 * @param $entity_id string Entity Q-ID
 	 * @return DataModel
 	 */
 	public function createDataModel( $entity_id = null ) {
 		return new \wb\DataModel( $this, $entity_id );
 	}
 
 	/**
 	 * Create an empty Wikibase data model related to this site
 	 *
 	 * @param $data object Single Entity object retrieved from wbgetentities API
 	 * @return DataModel
 	 */
 	public function createDataModelFromObject( $data ) {
 		$id = $data->id;
 		return \wb\DataModel::createFromObject( $data, $this, $id );
 	}
 
 }