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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 benchmark(store, n=10000):
 """ Iterates over all of the referreds, and then iterates over all of the referrers that refer to each one. Fairly item instantiation heavy. """

    R = Referrer

    for referred in store.query(Referred):
        for _reference in store.query(R, R.reference == referred):
            pass