@Override
    protected void doExecute(ExecutionContext context) {
        Optional<Tensor> tensor = ((TensorFieldValue)context.getCurrentValue()).getTensor();
        if (tensor.isEmpty()) return;
        Tensor packed = Tensors.packBits(tensor.get());
        context.setCurrentValue(new TensorFieldValue(packed));
    }
Returns whether this is a valid input or output from this.
indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/PackBitsExpression.java