[Maxima] How to simplify kdelta?

[Nicola Cabibbo]

Just trying to learn Maxima, with the commands:

	if get('itensor, 'version)=false then load (itensor) ;
	idim(3);
	dim:3;
	defcon(q,q,qq);
	expr:'levi_civita([i,k,m],[])*'levi_civita([],[i1,k,m])*q([], 
[i])*q([i1],[])$
	ishow(contract(expand(lc2kdt(expr))));

I obtain " 5*qq-kdelta*qq ". This is correct with kdelta=3, but
how can I directly obtain the simplified result "2 qq"?

Thanks for the attention

PS: my setup is (on a Mac)

wxMaxima 0.7.5 http://wxmaxima.sourceforge.net
Maxima 5.15.0 http://maxima.sourceforge.net
Using Lisp CMU Common Lisp Snapshot 2008-03 (19E)