% AllEIs is a mixture of positive and negative examples
cross_validation(AllEIs,):-
	set(cross_validation_method,leave-one-out),!,
	leave_one_out(AllEIs,AllEIs,)


set(cross_validation_method,folds).

	findall() % find number of folds -- so that you can decide number of iteration. 
	
	


How to deal with default? -- for leave-one-out 
Different fold. -- if you put the average -- then there is question 


[1,1,1,0,0],[1,1,1,1,0].

7/10=70%
(3/5+4/5)/2=7/10. -- you can see one particular fold  -- it is average over different rounds.