fn match_na<T: MatchArg>() -> Result<T, MatchArgError>Expand description
NA as a choice: pmatch(), and so the wrapper’s check, matches it as
the string "NA", so a choice that is "NA" or the only one starting
with it is selected. Anything else is MatchArgError::IsNa. No alias
maps it: the wrapper looks aliases up with match(), which never matches
NA to "NA".