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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:
 async def append_messages(self, name: str, messages: Sequence[AppendMessage], selected: SelectedMailbox = None) \ -> Tuple[AppendUid, Optional[SelectedMailbox]]: """Appends a message to the end of the mailbox. See Also: `RFC 3502 6.3.11. <https://tools.ietf.org/html/rfc3502#section-6.3.11>`_ Args: name: The name of the mailbox. messages: The messages to append. selected: If applicable, the currently selected mailbox name. Raises: :class:`~pymap.exceptions.MailboxNotFound` :class:`~pymap.exceptions.AppendFailure` """

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