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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 format_report_number(citation_elements):
 """Format report numbers that are missing a dash e.g. CERN-LCHH2003-01 to CERN-LHCC-2003-01 """

    re_report = re.compile(ur'^(?P<name>[A-Z-]+)(?P<nums>[\d-]+)$', re.UNICODE)
    for el in citation_elements:
        if el['type'] == 'REPORTNUMBER':
            m = re_report.match(el['report_num'])
            if m:
                name = m.group('name')
                if not name.endswith('-'):
                    el['report_num'] = m.group('name') + '-' + m.group('nums')
    return citation_elements