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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def postprocess_periodical(marc_xml, mods, uuid, counter, url):
 """ Some basic postprocessing of the periodical publications. Args: marc_xml (str):
 Original Aleph record. mods (str):
 XML string generated by XSLT template. uuid (str):
 UUID of the package. counter (int):
 Number of record, is added to XML headers. url (str):
 URL of the publication (public or not). Returns: str: Updated XML. """

    dom = double_linked_dom(mods)

    # TODO: Add more postprocessing

    add_missing_xml_attributes(dom, counter)

    if uuid:
        add_uuid(dom, uuid)

    return dom.prettify()