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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 _set_count(sets, n, **kwargs):
 """return the elements which occur n times over the sequence of sets Parameters sets : iterable of indexable objects n : int number of sets the element should occur in Returns ------- indexable indexable with all elements that occured in n of the sets Notes ----- used by both exclusive and intersection """

    sets = _set_preprocess(sets, **kwargs)
    i = as_index(_set_concatenate(sets), axis=0, base=True)
    # FIXME : this does not work for lex-keys
    return i.unique[i.count == n]