code: func Supports(featureList FeatureList, featureName string) bool {
  	for k, v := range featureList {
  		if featureName == string(k) {
  			return v.PreRelease != utilfeature.Deprecated
  		}
  	}
  	return false
  }
docs: // Supports indicates whether a feature name is supported on the given
  // feature set