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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 get_abbreviations(kb):
 """ For the sake of profiling. """

    return {"%s$$n%i" % (author.get_urn(), i): abbrev
                for author in kb.get_authors()
                for i, abbrev in enumerate(author.get_abbreviations())
                if author.get_urn() is not None}