anchor.diff:  list_unification_1(Exp1, Exp2)->
       LEs1 = [E||E<-Exp1,is_list(E)],
       LEs2 = [E||E<-Exp2,is_list(E)],
  -    case LEs1==[] andalso LEs2==[] of
  +    case LEs1==[] andalso LEs2==[] of 
           false ->
               case  has_meta_list(Exp1) of
                   false ->
  
positive.code:                                         is_meta_meta_list_variable(B);  
                                  _ -> false
                              end;
                          _ -> false
                      end;
                  _ ->
  
negative.code:                              H1Sub = create_sub(H1, lists:sublist(List2, I)),
                               Res=list_unification_1(T1, lists:nthtail(I, List2)),
                               combine_unification_results(H1Sub, Res)
                           end||I<-lists:seq(1,Len2-Len1)],
                      lists:append(Res)
              end;
          false ->
  