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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 _http_date(_date_str: str) -> Optional[datetime.datetime]: """Process a date string, return a datetime object """

        if _date_str is not None:
            timetuple = parsedate(_date_str)
            if timetuple is not None:
                return datetime.datetime(*timetuple[:6],
                                         tzinfo=datetime.timezone.utc)
        return None