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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 first(self):
 """Fetch the first row and then close the result set unconditionally. Returns None if no row is present. """

        if self._metadata is None:
            self._non_result()
        try:
            return (await self.fetchone())
        finally:
            await self.close()