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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 local_dt(dt):
 """Return an aware datetime in system timezone, from a naive or aware datetime. Naive datetime are assumed to be in UTC TZ. """

    if not dt.tzinfo:
        dt = pytz.utc.localize(dt)
    return LOCALTZ.normalize(dt.astimezone(LOCALTZ))