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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 utc_book_close_time(self):
 """ The book close time in utc. """

        tz = pytz.timezone(self.timezone)
        close_time = datetime.datetime.strptime(self.close_time, '%H:%M:%S').time()
        close_time = tz.localize(datetime.datetime.combine(datetime.datetime.now(tz), close_time))
        return close_time.astimezone(pytz.utc).time()