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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 next(self):
 """Return a column one by one :raises: StopIteration """

        if self._cur_col >= len(self._rec):
            self._cur_col = 0
            raise StopIteration
        col = self._rec[self._cur_col]
        self._cur_col += 1
        return col