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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):
 """ Returns the next row from the Instances object. :return: the next Instance object :rtype: Instance """

        if self.row < self.data.num_instances:
            index = self.row
            self.row += 1
            return self.data.get_instance(index)
        else:
            raise StopIteration()