This calls queries the external directory service to obtain the transitively-closed set of groups that the the subject_identifier is member of.

Return value
	type	description
	Set[string]	set of subject_identifiers that provides the group membership of subject_identifier passed as argument, it contains, recursively, all groups a subject_identifier is member of.
Parameters
name	type	description
session_id	session	valid session reference
subject_identifier	string	A string containing the subject_identifier, unique in the external directory service
Errors
name	arguments	description

• Message has only a synchronous version
• This is a custom message