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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 repr_timestamp(timestamp):
 """Return a debug representation of an HMC timestamp number."""

    if timestamp is None:
        return 'None'
    dt = datetime_from_timestamp(timestamp)
    ret = "%d (%s)" % (timestamp,
                       dt.strftime('%Y-%m-%d %H:%M:%S.%f %Z'))
    return ret