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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 send_at(self, value):
 """A unix timestamp specifying when your email should be delivered. :param value: A unix timestamp specifying when your email should be delivered. :type value: SendAt, int """

        if isinstance(value, SendAt):
            if value.personalization is not None:
                try:
                    personalization = \
                        self._personalizations[value.personalization]
                    has_internal_personalization = True
                except IndexError:
                    personalization = Personalization()
                    has_internal_personalization = False
                personalization.send_at = value.send_at

                if not has_internal_personalization:
                    self.add_personalization(
                        personalization, index=value.personalization)
            else:
                self._send_at = value
        else:
            self._send_at = SendAt(value)