(other-window) with negative argument

[H. Dieter Wilhelm]

Hello ()

I can't get a function to work with a negative argument of
(other-window).  When I'm using (other-window -1) in the *scratch*
buffer it is working as expected, as soon as I put it into a function
like the following

(defun previous-window ()
  (other-window -1))

or 

(defun previous-window ()
  "blabla"
  (interactive)
  (other-window -1))

and activate the function any call to (other-window -1) is opening the
debugger!

What am I doing wrong?

Thank you

      Dieter

I'm on "GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2018-06-17"
-- 
Best wishes
H. Dieter Wilhelm
Seeheim-Jugenheim, Germany