private static function popInvocation(WikiaMockProxyInvocation $invocation)
 {
     if (empty($invocation->uuid)) {
         return;
     }
     $stackInfo = $invocation->uuid;
     $index = $stackInfo['index'];
     // no match, something stupid happened
     if (count(self::$invocationStack) <= $index || $stackInfo !== $invocation->uuid) {
         // todo: log it
         Wikia::log(__METHOD__, false, "could not pop invocation: " . (string) $invocation);
         return;
     }
     self::$invocationStack = array_slice(self::$invocationStack, 0, $index);
 }