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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 to_timezone(dt, timezone):
 """ Return an aware datetime which is ``dt`` converted to ``timezone``. If ``dt`` is naive, it is assumed to be UTC. For example, if ``dt`` is "06:00 UTC+0000" and ``timezone`` is "EDT-0400", then the result will be "02:00 EDT-0400". This method follows the guidelines in http://pytz.sourceforge.net/ """

    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=_UTC)
    return timezone.normalize(dt.astimezone(timezone))