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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 __x_product (property_sets):
 """ Return the cross-product of all elements of property_sets, less any that would contain conflicting values for single-valued features. """

    assert is_iterable_typed(property_sets, property_set.PropertySet)
    x_product_seen = set()
    return __x_product_aux (property_sets, x_product_seen)[0]