value
(1) For name, a character (length-1 vector); for names, a character
vector of equal length to the number of VariableGroups beind modified; for
entities, either a character vector of variable URLs or a list containing a
combination of variable URLs and VariableGroups. Note that group names must
be unique, should be greater than 0 characters long, and "ungrouped" is a
reserved group name. (2) For duplicates, logical for whether duplicate
variable entries should be allowed in the VariableOrder.