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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 fetchmany(self, size=None):
 """Fetch several rows"""

        self._check_executed()
        if self._rows is None:
            return ()
        end = self.rownumber + (size or self.arraysize)
        result = self._rows[self.rownumber:end]
        self.rownumber = min(end, len(self._rows))
        return result