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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 shorter_name(key):
 """Return a shorter name for an id. Does this by only taking the last part of the URI, after the last / and the last #. Also replaces - and . with _. Parameters key: str Some URI Returns ------- key_short: str A shortened, but more ambiguous, identifier """

    key_short = key
    for sep in ['#', '/']:
        ind = key_short.rfind(sep)
        if ind is not None:
            key_short = key_short[ind+1:]
        else:
            key_short = key_short
    return key_short.replace('-', '_').replace('.', '_')