Octave 6.1.0 function has not yet been implemented

I just installed Octave 6.1.0 using the 64bit provided installer and when I try to use “c2d” from control package I get that the function has not yet been implemented even if it is. I searched online and doing
help @lti/c2d I get consistent answer … but I cannot get what I should do to make it running.
Thanks for the support

c2d is a class method. For it to be dispatched correctly, it must be called with an object of the correct class.
The following (from a BIST in that function) works for me:

pkg load control
A = [  1.0  0.5
       0.5  1.0 ].';
B = [  0.0 -1.0
       1.0  0.0 ].';
C = [ -1.0  0.0
       0.0  1.0 ].';
D = [  1.0  0.0
       0.0 -1.0 ].';
sys = c2d (ss (A, B, C, D), 2, "tustin");


you are perfectly right, thanks! It was my mistake, I was passing the wrong transfer function. The error output is misleading.
Thanks a lot