anchor.diff:      #callgraph{scc_order=Sccs, external_calls=_E} = build_callgraph(FilesToAnalyse),
       build_side_effect_tab(Sccs, LocalPlt, LibPlt),
       to_dets(LocalPlt, SideEffectFile),
  -    dets:close(LibSideEffectFile),
  +    dets:close(list_to_atom(LibSideEffectFile)),
       ets:delete(LocalPlt),
       ets:delete(LibPlt).
   
  
positive.code: 		    LocalPlt = from_dets(local_side_effect_plt, LocalSideEffectFile),
  		    Res = check_side_effect(Node, LibPlt, LocalPlt),
  		    dets:close(LibSideEffectFile),
  		    dets:close(LocalSideEffectFile),
  		    ets:delete(LocalPlt),
  		    ets:delete(LibPlt),
  		    Res
  
negative.code: 
  -spec(has_side_effect(File::filename(), Node::syntaxTree(), SearchPaths::[dir()])-> true|false|unknown).
  has_side_effect(File, Node, SearchPaths) ->
      LibSideEffectFile = list_to_atom(filename:join(?WRANGLER_DIR, "plt/side_effect_plt")),
      LibPlt = from_dets(lib_side_effect_plt, LibSideEffectFile),
      Res = check_side_effect(Node, LibPlt, none), 
      case Res of 
  