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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 timezone(self):
 """The name of the time zone for the location. A list of time zone names can be obtained from pytz. For example. """


        if not self._timezone_group and not self._timezone_location:
            return None

        if self._timezone_location != "":
            return "%s/%s" % (self._timezone_group, self._timezone_location)
        else:
            return self._timezone_group