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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 rm_empty_doi(d):
 """ If an "identifier" dictionary has no doi ID, then it has no use. Delete it. :param dict d: Metadata :return dict d: Metadata """

    logger_misc.info("enter remove_empty_doi")
    try:
        # Check each publication dictionary
        for pub in d['pub']:
            # If no identifier, then we can quit here. If identifier, then keep going.
            if 'identifier' in pub:
                if 'id' in pub['identifier'][0]:
                    # If there's a DOI id, but it's EMPTY
                    if pub['identifier'][0]['id'] in EMPTY:
                        del pub['identifier']
                else:
                    # If there's an identifier section, with no DOI id
                    del pub['identifier']
    except KeyError as e:
        # What else could go wrong?
        logger_misc.warn("remove_empty_doi: KeyError: publication key not found, {}".format(e))
    logger_misc.info("exit remove_empty_doi")
    return d