@Override
    public Response push(Context context, Shape shape, Receiver next) {
        if (matchesAttribute(shape, context)) {
            return next.apply(context, shape);
        } else {
            return Response.CONTINUE;
        }
    }
Matches shapes with a specific attribute or that matches an attribute comparator.
smithy-model/src/main/java/software/amazon/smithy/model/selector/AttributeSelector.java