docs: def logical_raid_levels(self):
          """Gets the raid level for each logical volume
  
          :returns the set of list of raid levels configured.
          """
          lg_raid_lvls = set()
          for member in self.get_members():
              lg_raid_lvls.add(mappings.RAID_LEVEL_MAP_REV.get(member.raid))
          return lg_raid_lvls