anchor.diff:  		Result		:: {Op, Path, Value} | {error, Reason},
   		Op				:: string(),
   		Path			:: string(),
  -		Value			:: string() | tuple(),
  +		Value			:: string() | tuple() | atom(),
   		Reason		:: malformed_request.
   %% @doc validate elements in an operation object and return
   %% `op', `path' and `value' or reason for failed.
  
positive.code: 	UpdateSubscriber =
  		Subscriber#subscriber{multisession = MultiSession},
  	do_write(UpdateSubscriber);
  patch_replace1("multisession", Id, Value) ->
  	[Subscriber] = mnesia:read(subscriber, Id),
  	UpdateSubscriber =
  		Subscriber#subscriber{multisession = Value},
  
negative.code: 	when
  		Id				:: binary(),
  		Path			:: string(),
  		Value			:: string() | atom() | tuple().
  %% @doc replace the give value with given target path.
  patch_replace(Id, Path , Value) ->
  	[Target] = string:tokens(Path, "/"),
  