anchor.diff:                            (:strict (error "Coudn't load ~A" dependency))))))))
      :test #'library-version=))
   
  -(defun validate-library-versions-list (versions-list)
  -  (loop for i from 0 to (1- (length versions-list))
  -     for vi = (elt versions-list i)
  -     do
  -       (loop for j from 1 to (1- (length versions-list))
  -          for vj = (elt versions-list j)
  -          when (and (not (equalp i j))
  -                    (and (equalp (library-name (library vi))
  -                                 (library-name (library vj)))
  -                         (and (version vi)
  -                              (version vj)
  -                              (not (equalp (version vi)
  -                                           (version vj))))))
  -          do (error "Cannot load ~A and ~A" vi vj))))
  -
   (defun pick-library-version (library-versions)
     "Picks a version from a library list of versions"
     (let ((library-version (first library-versions)))
  
positive.code: 	;; Calculate list of library-versions involved
  	(let ((library-versions-involved
  	       (calculate-library-versions-involved library-version)))
  
  	  ;; Validate the library versions list
                                          ;(validate-library-versions-list library-versions)
  
  	  (let ((library-versions (pbo-solve-library-versions library-version
  							      library-versions-involved)))
  	    ;; Remove the project library from the library versions list
  
negative.code: 	(let ((library-versions-involved
  	       (calculate-library-versions-involved library-version)))
  
  	  (let ((library-versions (pbo-solve-library-versions library-version
  							      library-versions-involved)))
  	    ;; Remove the project library from the library versions list
  