code: func (c *CgroupsValidator) Validate(spec SysSpec) (error, error) {
  	subsystems, err := c.getCgroupSubsystems()
  	if err != nil {
  		return nil, errors.Wrap(err, "failed to get cgroup subsystems")
  	}
  	return nil, c.validateCgroupSubsystems(spec.Cgroups, subsystems)
  }
docs: // Validate is part of the system.Validator interface.