private static Tensor tensorFromMappedValueString(String valueString, Optional<TensorType> type) {
        try {
            valueString = valueString.trim();
            Tensor.Builder builder = Tensor.Builder.of(type.orElse(typeFromMappedValueString(valueString)));
            MappedValueParser parser = new MappedValueParser(valueString, builder);
            parser.parse();
            return builder.build();
        }
        catch (NumberFormatException e) {
            throw new IllegalArgumentException("Excepted a number or a string starting by '{' or 'tensor('");
        }
    }
Derives the tensor type from the first address string in the given tensor string
vespajlib/src/main/java/com/yahoo/tensor/TensorParser.java