code: func (a *API) FetchRuleSet(cid CIDType) (*RuleSet, error) {
  	if cid == nil || *cid == "" {
  		return nil, fmt.Errorf("Invalid rule set CID [none]")
  	}
  
  	rulesetCID := string(*cid)
  
  	matched, err := regexp.MatchString(config.RuleSetCIDRegex, rulesetCID)
  	if err != nil {
  		return nil, err
  	}
  	if !matched {
  		return nil, fmt.Errorf("Invalid rule set CID [%s]", rulesetCID)
  	}
  
  	result, err := a.Get(rulesetCID)
  	if err != nil {
  		return nil, err
  	}
  
  	if a.Debug {
  		a.Log.Printf("[DEBUG] fetch rule set, received JSON: %s", string(result))
  	}
  
  	ruleset := &RuleSet{}
  	if err := json.Unmarshal(result, ruleset); err != nil {
  		return nil, err
  	}
  
  	return ruleset, nil
  }
docs: // FetchRuleSet retrieves rule set with passed cid.