anchor.diff:      end.
   
   
  --spec alter_user(username(), options()) ->
  +-spec alter_user(Username :: string(), options()) ->
       ok | {error, term()}.
   alter_user("all", _Options) ->
       {error, reserved_name};
  
positive.code:             end
      end.
  
  -spec del_user(username()) ->
      ok | {error, term()}.
  del_user("all") ->
      {error, reserved_name};
  
negative.code:             end
      end.
  
  -spec add_user(Username :: string(), options()) ->
      ok | {error, term()}.
  add_user(Username, Options) ->
      add_role(name2bin(Username), Options,
  