private function parseNamespace(\ArrayIterator $tokens)
    {
        // skip to the first string or namespace separator
        $this->skipToNextStringOrNamespaceSeparator($tokens);

        $name = '';
        while ($tokens->valid() && ($tokens->current()[0] === T_STRING || $tokens->current()[0] === T_NS_SEPARATOR)
        ) {
            $name .= $tokens->current()[1];
            $tokens->next();
        }

        return $name;
    }