def convertCatalogResultsToXml(result_set):
    """ Convert a set of results (catalog Brain results) to XML using the
        get_xml method of those results.

        result_set must be an object capable of being iterated over.
    """
    xmlstream = []

    for result in result_set:
        file_object = result.getObject()
        xmlstream.append(file_object.get_xml())

    xmlstream = map(lambda x: str(x), xmlstream)

    return '\n\n'.join(xmlstream)