@send_at.setter<EOL><INDENT>def send_at(self, value):<DEDENT>
if isinstance(value, SendAt):<EOL><INDENT>if value.personalization is not None:<EOL><INDENT>try:<EOL><INDENT>personalization =self._personalizations[value.personalization]<EOL>has_internal_personalization = True<EOL><DEDENT>except IndexError:<EOL><INDENT>personalization = Personalization()<EOL>has_internal_personalization = False<EOL><DEDENT>personalization.send_at = value.send_at<EOL>if not has_internal_personalization:<EOL><INDENT>self.add_personalization(<EOL>personalization, index=value.personalization)<EOL><DEDENT><DEDENT>else:<EOL><INDENT>self._send_at = value<EOL><DEDENT><DEDENT>else:<EOL><INDENT>self._send_at = SendAt(value)<EOL><DEDENT>
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