even more problems working with files [obsolete]

As I already wrote: I found my mistake myself. I should have used

  let TestFile = Storage.open('4testing','w');
  if (TestFile.write('Hello, World!')) {
    print('file "4testing" was successfully created');
  } else {
    print('file "4testing" could not be created');
  }

for creating the file.

Sorry for bothering you!