This method has two variants:
*:int Insert(const char*, bool check_for_dups=true)
*:int Insert(ExprTree*, bool check_for_dups=true)

New {quote:ClassAds} already have a compatibility version of the first variant.

For the second variant, we'd probably use new {quote:ClassAds}' Insert(), which takes the attribute name and value as separate arguments.

The check_for_dups argument does not appear to be used anywhere.

Developer time: ???