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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 _maybe_release_last_part(self) -> None: """Ensures that the last read body part is read completely."""

        if self._last_part is not None:
            if not self._last_part.at_eof():
                await self._last_part.release()
            self._unread.extend(self._last_part._unread)
            self._last_part = None