code: func GetCgroupSubsystems() (*CgroupSubsystems, error) {
  	// get all cgroup mounts.
  	allCgroups, err := libcontainercgroups.GetCgroupMounts(true)
  	if err != nil {
  		return &CgroupSubsystems{}, err
  	}
  	if len(allCgroups) == 0 {
  		return &CgroupSubsystems{}, fmt.Errorf("failed to find cgroup mounts")
  	}
  	mountPoints := make(map[string]string, len(allCgroups))
  	for _, mount := range allCgroups {
  		for _, subsystem := range mount.Subsystems {
  			mountPoints[subsystem] = mount.Mountpoint
  		}
  	}
  	return &CgroupSubsystems{
  		Mounts:      allCgroups,
  		MountPoints: mountPoints,
  	}, nil
  }
docs: // GetCgroupSubsystems returns information about the mounted cgroup subsystems