How to create an empty folder in GDScript?
You can create easily an empty folder by passing the path, something like this should create just an empty folder:
func _ready( ):
# Creates an empty folder.
var directory = Directory.new( )
# Then you could create for example a new file like you already do with:
var file = File.new( )
# Note here the file extension ".txt"
Note here, that you specify in your path what format your file should have. You missed an extension here! Try to extend your path with ".txt" or another format you want.
see make_dir and the descrpition of File for more information