Request to add operation 'required_expected_variables' as the combination of required_variables and expected_variables

Requesting to add operation 'required_expected_variables' as the combination of required_variables and expected_variables, to retrieve the Library IG variables with Core = 'Req' and Core = 'Exp' in only 1 list of variables, ordered by the variable's Ordinal.

It would allow us to improve checks: data against the Library and, when available, Define-XML against the Library.
Note: the variables that are to be present in a dataset (or its Define-XML document) include both Core ‘Req’ and ‘Exp’ and combined in the relative order indicated in the IG