code: func NewDevServiceFromCertFiles(serviceID string, logger *log.Logger,
  	caFile, certFile, keyFile string) (*Service, error) {
  
  	tlsCfg, err := devTLSConfigFromFiles(caFile, certFile, keyFile)
  	if err != nil {
  		return nil, err
  	}
  	return NewDevServiceWithTLSConfig(serviceID, logger, tlsCfg)
  }
docs: // NewDevServiceFromCertFiles creates a Service using certificate and key files
  // passed instead of fetching them from the client.