The create method returns void.

src/Storage/AccessTokenInterface.php

@@ -38,7 +38,7 @@ interface AccessTokenInterface extends StorageInterface
      * @param  string         $token      The access token
      * @param  integer        $expireTime The expire time expressed as a unix timestamp
      * @param  string|integer $sessionId  The session ID
-     * @return \League\OAuth2\Server\Entity\AccessTokenEntity
+     * @return void
      */
     public function create($token, $expireTime, $sessionId);