UserGroupType (type)

{
  "enum": [
    "read_only_api_users", 
    "read_write_api_users", 
    "superusers", 
    "undefined"
  ], 
  "id": "UserGroupType", 
  "module_id": "CertificateManager", 
  "title": "Supported groups a principal identity can belong to.", 
  "type": "string"
}