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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 ctime(self, timezone=None):
 """Returns a ctime string. :param timezone = self.timezone The timezone (in seconds west of UTC) to return the value in. By default, the timezone used when constructing the class is used (local one by default). To use UTC, use timezone = 0. To use the local tz, use timezone = chronyk.LOCALTZ. """

        if timezone is None:
            timezone = self.timezone
        return time.ctime(self.__timestamp__ - timezone)