import unitypackage with script

hi guys, i want to import a unitypackage to my project. i use this code:

AssetDatabase.ImportPackage(Application.dataPath+"/package.unitypackage",true);

but Nothing is added to the project

are you sure thats the path you want? I ask because that would be within the Assets folder.
Sounds like you potentially want

AssetDatabase.ImportPackage(Application.dataPath+"/../package.unitypackage",true);

yes i am sure, i change the path but it does not work.
can you give me a simple example?