set_list_2_combinations.Rd
note that set order in names is derived from size of the sets, biggest first also a none set with an empty string as a value is added by default
set_list_2_combinations(set_list, add_empty = TRUE)
a named list where the names are the sets and the values vectors of things in those sets
should an option to include an empty set be included? if true (the default) adds an item called none with the value of an empty string
a list of combinations of sets