Sub devices and Sysman API

Maybe just a clarification is needed. But I see this in the specification:

https://spec.oneapi.io/level-zero/latest/core/PROG.html#sub-device-support

** a sub-device can be partitioned into more sub-devices; e.g. down to a single slice.**

Let's say I wanted to enumerate all the sub-devices on a device, does this mean I need to recursively call zeDeviceGetSubDevices
until I get zero sub-devices or does the root device enumerate all possible sub-devices directly with a single call?

I ask because the Sysman API notes that

A Sysman device handle operates at the device level. If a sub-device device handle is passed to any of the Sysman functions, the result will be as if the device handle was used.

If there are sub-devices strictly under sub-devices, then what would a Sysman call with argument device.sub_device.sub_device refer to? device or device.sub_device?

Start with the linked Level Zero sub-device support specification and the Sysman API notes quoted in the issue. Determine whether sub-devices must be enumerated recursively and what a Sysman call receives for nested handles; done means the specification clearly defines both behaviors.