The remaining elements of the argument are DS updates. The order of this list is
the same as the order the data sources were defined in the RRA.
If there is no data for a certain data-source, the letter
-B<U> (eg. N:0.1:U:1) can be defined.
+B<U> (e.g., N:0.1:U:1) can be defined.
The format of the value acquired from the data source is dependent of the
data source type chosen. Normally it will be numeric, but the data acquisition