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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_preprocess(sets, **kwargs):
 """upcasts a sequence of indexable objects to Index objets according to the given kwargs Parameters sets : iterable of indexable objects axis : int, optional axis to view as item sequence assume_unique : bool, optional if we should assume the items sequence does not contain duplicates Returns ------- list of Index objects Notes ----- common preprocessing for all set operations """

    axis            = kwargs.get('axis', semantics.axis_default)
    assume_unique   = kwargs.get('assume_unique', False)

    if assume_unique:
        sets = [as_index(s, axis=axis).unique for s in sets]
    else:
        sets = [as_index(s, axis=axis).unique for s in sets]
    return sets