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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_utc(value, defaulttz=None):
 """Convert datetime.datetime time to UTC If value doesn't have tzinfo, then defaulttz is set. Default value of defaulttz is local time zone. """

    if defaulttz is None:
        defaulttz = tzlocal()
    return _convert(value, tzutc(), defaulttz)