public function nextOutdent()
    {
        $oldLevel = $this->getIndentLevel();
        $expected = $this->getLevel();

        if ($expected < $oldLevel) {
            $newLevel = $this->outdent();
            if ($newLevel < $expected) {
                $this->throwException(
                    'Inconsistent indentation. '.
                    'Expecting either '.
                    $newLevel.
                    ' or '.
                    $oldLevel.
                    ' spaces/tabs.'
                );
            }

            return $newLevel;
        }

        return false;
    }