code: func (a APIObjectVersioner) ParseResourceVersion(resourceVersion string) (uint64, error) {
  	if resourceVersion == "" || resourceVersion == "0" {
  		return 0, nil
  	}
  	version, err := strconv.ParseUint(resourceVersion, 10, 64)
  	if err != nil {
  		return 0, storage.NewInvalidError(field.ErrorList{
  			// Validation errors are supposed to return version-specific field
  			// paths, but this is probably close enough.
  			field.Invalid(field.NewPath("resourceVersion"), resourceVersion, err.Error()),
  		})
  	}
  	return version, nil
  }
docs: // ParseResourceVersion takes a resource version argument and converts it to
  // the etcd version. For watch we should pass to helper.Watch(). Because resourceVersion is
  // an opaque value, the default watch behavior for non-zero watch is to watch
  // the next value (if you pass "1", you will see updates from "2" onwards).