public function replacePrefixWithUri($prefixedString, $prefixes)
    {
        // check for qname. a qname was given if a : was found, but no < and >
        if (false !== strpos($prefixedString, ':') &&
            false === strpos($prefixedString, '<') && false === strpos($prefixedString, '>')) {
            // prefix is the part before the :
            $prefix = substr($prefixedString, 0, strpos($prefixedString, ':'));

            // if a prefix
            if (true === isset($prefixes[$prefix])) {
                $prefixedString = str_replace($prefix.':', $prefixes[$prefix], $prefixedString);
            }
        }

        return $prefixedString;
    }