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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_aux (property_sets, seen_features):
 """Returns non-conflicting combinations of property sets. property_sets is a list of PropertySet instances. seen_features is a set of Property instances. Returns a tuple of: - list of lists of Property instances, such that within each list, no two Property instance have the same feature, and no Property is for feature in seen_features. - set of features we saw in property_sets """

    assert is_iterable_typed(property_sets, property_set.PropertySet)
    assert isinstance(seen_features, set)
    if not property_sets:
        return ([], set())

    properties = property_sets[0].all()

    these_features = set()
    for p in property_sets[0].non_free():
        these_features.add(p.feature)

    # Note: the algorithm as implemented here, as in original Jam code, appears to
    # detect conflicts based on features, not properties. For example, if command
    # line build request say:
    #
    # <a>1/<b>1 c<1>/<b>1
    #
    # It will decide that those two property sets conflict, because they both specify
    # a value for 'b' and will not try building "<a>1 <c1> <b1>", but rather two
    # different property sets. This is a topic for future fixing, maybe.
    if these_features & seen_features:

        (inner_result, inner_seen) = __x_product_aux(property_sets[1:], seen_features)
        return (inner_result, inner_seen | these_features)

    else:

        result = []
        (inner_result, inner_seen) = __x_product_aux(property_sets[1:], seen_features | these_features)
        if inner_result:
            for inner in inner_result:
                result.append(properties + inner)
        else:
            result.append(properties)

        if inner_seen & these_features:
            # Some of elements in property_sets[1:] conflict with elements of property_sets[0],
            # Try again, this time omitting elements of property_sets[0]
            (inner_result2, inner_seen2) = __x_product_aux(property_sets[1:], seen_features)
            result.extend(inner_result2)

        return (result, inner_seen | these_features)