code: func NewDiscoveryCategoryExpander(client discovery.DiscoveryInterface) CategoryExpander {
  	if client == nil {
  		panic("Please provide discovery client to shortcut expander")
  	}
  	return discoveryCategoryExpander{discoveryClient: client}
  }
docs: // NewDiscoveryCategoryExpander returns a category expander that makes use of the "categories" fields from
  // the API, found through the discovery client. In case of any error or no category found (which likely
  // means we're at a cluster prior to categories support, fallback to the expander provided.