code: func (va *ValidationAuthorityImpl) checkCAARecords(
  	ctx context.Context,
  	identifier core.AcmeIdentifier,
  	params *caaParams) (bool, bool, []*dns.CAA, error) {
  	hostname := strings.ToLower(identifier.Value)
  	// If this is a wildcard name, remove the prefix
  	var wildcard bool
  	if strings.HasPrefix(hostname, `*.`) {
  		hostname = strings.TrimPrefix(identifier.Value, `*.`)
  		wildcard = true
  	}
  	caaSet, records, err := va.getCAASet(ctx, hostname)
  	if err != nil {
  		return false, false, nil, err
  	}
  	present, valid := va.validateCAASet(caaSet, wildcard, params)
  	return present, valid, records, nil
  }
docs: // checkCAARecords fetches the CAA records for the given identifier and then
  // validates them. If the identifier argument's value has a wildcard prefix then
  // the prefix is stripped and validation will be performed against the base
  // domain, honouring any issueWild CAA records encountered as appropriate.
  // checkCAARecords returns four values: the first is a bool indicating whether
  // CAA records were present after filtering for known/supported CAA tags. The
  // second is a bool indicating whether issuance for the identifier is valid. The
  // unmodified *dns.CAA records that were processed/filtered are returned as the
  // third argument. Any  errors encountered are returned as the fourth return
  // value (or nil).