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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 _strptime(self, time_str):
 """Convert an ISO 8601 formatted string in UTC into a timezone-aware datetime object."""

        if time_str:
            # Parse UTC string into naive datetime, then add timezone
            dt = datetime.strptime(time_str, __timeformat__)
            return dt.replace(tzinfo=UTC())
        return None