code: func (e discoveryCategoryExpander) Expand(category string) ([]schema.GroupResource, bool) {
  	// Get all supported resources for groups and versions from server, if no resource found, fallback anyway.
  	apiResourceLists, _ := e.discoveryClient.ServerResources()
  	if len(apiResourceLists) == 0 {
  		return nil, false
  	}
  
  	discoveredExpansions := map[string][]schema.GroupResource{}
  	for _, apiResourceList := range apiResourceLists {
  		gv, err := schema.ParseGroupVersion(apiResourceList.GroupVersion)
  		if err != nil {
  			continue
  		}
  		// Collect GroupVersions by categories
  		for _, apiResource := range apiResourceList.APIResources {
  			if categories := apiResource.Categories; len(categories) > 0 {
  				for _, category := range categories {
  					groupResource := schema.GroupResource{
  						Group:    gv.Group,
  						Resource: apiResource.Name,
  					}
  					discoveredExpansions[category] = append(discoveredExpansions[category], groupResource)
  				}
  			}
  		}
  	}
  
  	ret, ok := discoveredExpansions[category]
  	return ret, ok
  }
docs: // Expand fulfills CategoryExpander