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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 _rfc3339_to_datetime(dt_str):
 """Convert a microsecond-precision timestamp to a native datetime. :type dt_str: str :param dt_str: The string to convert. :rtype: :class:`datetime.datetime` :returns: The datetime object created from the string. """

    return datetime.datetime.strptime(dt_str, _RFC3339_MICROS).replace(tzinfo=UTC)