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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 iterate(self, index, step, n_cols=70):
 """ Return an iterator that starts and the current index and increments by the given step. """


        while True:
            if step < 0 and index < 0:
                # Hack to prevent displaying a submission's post if iterating
                # comments in the negative direction
                break
            try:
                yield self.get(index, n_cols=n_cols)
            except IndexError:
                break
            index += step