default Tensor rename(List<String> fromDimensions, List<String> toDimensions) {
        return new Rename<>(new ConstantTensor<>(this), fromDimensions, toDimensions).evaluate();
    }
Aggregates cells over a set of dimensions, or over all dimensions if no dimensions are specified
vespajlib/src/main/java/com/yahoo/tensor/Tensor.java