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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 _astimezone_ts(self, timezone):
 """Changes the time zones of all timestamps. Receives a new timezone and applies to all timestamps, if necessary. Args: timezone (:obj:`tzinfo`):
 Time zone to be applied Returns: A new ``Timestamps`` object if the time zone changes, otherwise returns ``self``. """

    if self.created.tzinfo is timezone:
        return self
    else:
        nw_obj = Timestamps((None,)*4)
        nw_obj.created = self.created.astimezone(timezone)
        nw_obj.changed = self.changed.astimezone(timezone)
        nw_obj.mft_changed = self.mft_changed.astimezone(timezone)
        nw_obj.accessed = self.accessed.astimezone(timezone)

        return nw_obj