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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 get(self):
 """ Get a JSON-ready representation of this Mail object. :returns: This Mail object, ready for use in a request body. :rtype: dict """

        mail = {
            'from': self._get_or_none(self.from_email),
            'subject': self._get_or_none(self.subject),
            'personalizations': [p.get() for p in self.personalizations or []],
            'content': [c.get() for c in self.contents or []],
            'attachments': [a.get() for a in self.attachments or []],
            'template_id': self._get_or_none(self.template_id),
            'sections': self._flatten_dicts(self.sections),
            'headers': self._flatten_dicts(self.headers),
            'categories': [c.get() for c in self.categories or []],
            'custom_args': self._flatten_dicts(self.custom_args),
            'send_at':  self._get_or_none(self.send_at),
            'batch_id': self._get_or_none(self.batch_id),
            'asm': self._get_or_none(self.asm),
            'ip_pool_name': self._get_or_none(self.ip_pool_name),
            'mail_settings': self._get_or_none(self.mail_settings),
            'tracking_settings': self._get_or_none(self.tracking_settings),
            'reply_to': self._get_or_none(self.reply_to),
        }

        return {key: value for key, value in mail.items()
                if value is not None and value != [] and value != {}}