code: func OptionGeneric(generic map[string]interface{}) SandboxOption {
  	return func(sb *sandbox) {
  		if sb.config.generic == nil {
  			sb.config.generic = make(map[string]interface{}, len(generic))
  		}
  		for k, v := range generic {
  			sb.config.generic[k] = v
  		}
  	}
  }
docs: // OptionGeneric function returns an option setter for Generic configuration
  // that is not managed by libNetwork but can be used by the Drivers during the call to
  // net container creation method. Container Labels are a good example.