Direct the citation elements based on their qualifier.

def citation_director(**kwargs):
    """Direct the citation elements based on their qualifier."""
    qualifier = kwargs.get('qualifier', '')
    content = kwargs.get('content', '')
    if qualifier == 'publicationTitle':
        return CitationJournalTitle(content=content)
    elif qualifier == 'volume':
        return CitationVolume(content=content)
    elif qualifier == 'issue':
        return CitationIssue(content=content)
    elif qualifier == 'pageStart':
        return CitationFirstpage(content=content)
    elif qualifier == 'pageEnd':
        return CitationLastpage(content=content)
    else:
        return None