save reply/forward and retrieve the item result for further modification,
        you may want to use account.drafts as the folder.

def save(self, folder):
        """
        save reply/forward and retrieve the item result for further modification,
        you may want to use account.drafts as the folder.
        """
        if not self.account:
            raise ValueError('%s must have an account' % self.__class__.__name__)
        res = self.account.bulk_create(items=[self], folder=folder, message_disposition=SAVE_ONLY)
        if res and isinstance(res[0], Exception):
            raise res[0]
        res = list(self.account.fetch(res)) # retrieve result
        if res and isinstance(res[0], Exception):
            raise res[0]
        return res[0]