code: func (api UsersAPI) RemoveTOTP(w http.ResponseWriter, r *http.Request) {
  	username := mux.Vars(r)["username"]
  
  	valMngr := validationdb.NewManager(r)
  	hasValidatedPhones, err := valMngr.HasValidatedPhones(username)
  	if err != nil {
  		log.Error(err)
  		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
  		return
  	}
  	if !hasValidatedPhones {
  		w.WriteHeader(http.StatusConflict)
  		return
  	}
  	totpMgr := totp.NewManager(r)
  	err = totpMgr.Remove(username)
  	if err != nil && !totpMgr.IsErrNotFound(err) {
  		log.Error(err)
  		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
  		return
  	}
  	// if the err is an error not found, there was nothing in the first place
  	w.WriteHeader(http.StatusNoContent)
  }
docs: // RemoveTOTP is the handler for DELETE /users/{username}/totp/
  // Removes TOTP authentication for this user, if possible.