code: func (api UsersAPI) DeletePublicKey(w http.ResponseWriter, r *http.Request) {
  	username := mux.Vars(r)["username"]
  	label := mux.Vars(r)["label"]
  	userMgr := user.NewManager(r)
  
  	usr, err := userMgr.GetByName(username)
  	if err != nil {
  		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
  		return
  	}
  
  	_, err = usr.GetPublicKeyByLabel(label)
  	if err != nil {
  		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
  		return
  	}
  
  	if err := userMgr.RemovePublicKey(username, label); err != nil {
  		log.Error("ERROR while removing public key:\n", err)
  		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
  		return
  	}
  
  	w.WriteHeader(http.StatusNoContent)
  }
docs: // DeletePublicKey Deletes a public key