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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 _bibliography(doc, terms, converters=[], format='html'):
 """ Render citations, from a document or a doct of dicts If the input is a dict, each key is the name of the citation, and the value is a BibTex formatted dict :param doc: A MetatabDoc, or a dict of BibTex dicts :return: """


    output_backend = 'latex' if format == 'latex' else MetatabHtmlBackend

    def mk_cite(v):
        for c in converters:
            r = c(v)

            if r is not False:
                return r

        return make_citation_dict(v)

    if isinstance(doc, MetatabDoc):
        # This doesn't work for LaTex, b/c the formatter adds the prologue and epilogue to eery entry

        d = [mk_cite(t) for t in terms]

        cd = {e['name_link']: e for e in d}

    else:

        cd = {k: mk_cite(v, i) for i, (k, v) in enumerate(doc.items())}

    # for k, v in cd.items():
    #    print (k, v)

    return PybtexEngine().format_from_string(safe_dump({'entries': cd}),
                                             style=MetatabStyle,
                                             output_backend=output_backend,
                                             bib_format='yaml')