def render(self, session, logger, resourcegroup, required_type,
hostname, cluster, **arguments):
validate_basic("resourcegroup", resourcegroup)
if required_type is not None:
Resource.polymorphic_subclass(required_type,
"Unknown resource type")
if required_type == "resourcegroup":
raise ArgumentError("A resourcegroup can't hold other "
"resourcegroups.")
holder = get_resource_holder(session, hostname, cluster, compel=False)
ResourceGroup.get_unique(session, name=resourcegroup, holder=holder,
preclude=True)
dbrg = ResourceGroup(name=resourcegroup, required_type=required_type)
return add_resource(session, logger, holder, dbrg)
